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Small area spread and step-like changes in emergency medical admissions in response to an apparently new type of infectious event

Rodney P Jones

Healthcare Analysis & Forecasting, Camberley, UK

E-mail : hcaf_rod@yahoo.co.uk

DOI: 10.15761/FGNAMB.100110

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Abstract

Three potential outbreaks of an infectious-like agent are documented within 230very small area geographies called mid and lower super output areas (MSOA, LSOA) in Wigan on the outskirts of greater Manchester in the UK, using a method which detects step-like increases in medical admissions. These events could be more correctly described as rectangular waves which show spatiotemporal spread. The events are clustered around the years 2008, 2010 and 2012, and in the small areas the effect of each event endures for a period of around 12 months before eventually abating, i.e. the rectangular wave effect. All admissions occur at the Wigan Royal Infirmary (precluding hospital admission threshold effects), and the majority of admissions are for residents of the Wigan local authority (roughly 16 x 12 km), which is covered by a single primary care organization (PCO) - precluding PCO, social care policy, funding and management effects. The small size of the Wigan area precludes effects due to the weather or environment. The timing and magnitude of the 2010 event was investigated in detail, while the date and magnitude of the largest event in each MSOA/LSOA between 2008 and 2013 was also documented. For small areas with an average of 100 medical admissions per annum, the maximum step-increase ranges from +10% to +100%, which is outside of the 85% confidence interval for Poisson-based variation. The magnitude of the increase is independent of deprivation and population density, but shows evidence of an effect due to age. These results confirm the results for other small area studies conducted elsewhere in the UK, and point to the existence of a major new type of infectious event.

Key words

 medical admissions, inflammation, emerging infectious diseases, England, Wigan borough, cytomegalovirus, small area epidemiologic studies, moving rectangular wave, spatiotemporal studies

Introduction

As of 2005 there were 1,407 species of known human pathogens [1]. New viruses are being discovered at around two per year, and around 100 to 560 are estimated to be yet discovered [2]. Studies between 2001 and 2007 using 16S ribosome DNA analysis discovered 15 new bacterial genera and 215 new species [3], while a single study between 2006 and 2010 in Utah (USA) using clinical specimens discovered a further 111 novel genera and 673 novel species [4]. Humans are exposed to multiple pathogens, and a study of Mexican Americans found that that over 55% of persons had antigens against eight or more of 13 common pathogens [5], many of which create persistent infections [6].

Simultaneous exposure to multiple pathogens has been called the ‘pathogen burden’, and a number of common diseases appear to have increased incidence or severity as the pathogen burden increases [7-11]. Within this context, it should not be a surprise if novel types of disease outbreaks begin to be characterized which will exhibit complex patterns of spread. For example, a relatively difficult to transmit pathogen (with multiple strains) which evokes a respiratory phase during (re)infection, may be expected to show mixed slow/burst spatial spread [12].

The availability of computerized hospital admission data in England from the early 1990’s onward, has allowed the identification of one such novel series of infectious-like events which are specific to a particular set of medical conditions apparently linked to infection, inflammation and autoimmunity [13-16]. Analysis of increased deaths associated with these events indicates that they appear to stretch back to the 1950’s with around two events per decade, although a four-in-a-row series occurred in the 1990’s at roughly three year intervals, and another four-in-a-row series occurred between 2008 and 2014 at two year intervals [17-19]. Increased deaths, medical admissions, emergency department attendances, NHS staff sickness absence and general practitioner referrals all show spatiotemporal spread during these infectious-like events [19-27], with full spatial spread across the UK appearing to take around two years while spread between the small areas which constitute a local authority take around 18 months [17-27].

This study analyzes very small area data covering the more recent 2008, 2010 and 2012 events for medical admissions to the Wigan Royal Infirmary located near the center of the Wigan borough council on the outskirts of greater Manchester in northern England. The bulk of these admissions are covered by a single primary care organization (PCO), the Wigan Borough Clinical Commissioning Group, hence any small area differences cannot arise from differences in acute admission thresholds, differences in PCO policies or practice, or to differences in adult social services. The findings from previous studies [24] are extended into very small area geographies called Lower Super Output Areas (LSOA) which contain around 100 medical admissions per annum, and use daily rather than monthly admissions to characterize a unique step-like increase in admissions which may best be described as a moving rectangular wave, in which admissions stay high for 12 months before rapidly reverting back to the baseline trajectory.

It has only recently been discovered that one of these events occurred in 2010 [18,19], and this event in particular can be investigated in more detail, along with the issue of spatiotemporal granularity/heterogeneity and infectious bursts which are a known feature of infectious outbreaks [28-31].

Methods

The data covers daily emergency (non-elective) medical admissions between April 2008 and March 2013, and comes from a previous study which used larger mid super output areas (MSOA), and examined the 2012 event in detail [24]. Medical admissions covers the specialties General & Elderly Medicine (55%), Emergency Assessment (18%), Thoracic medicine (11%), Cardiology (10%), Gastroenterology (6%) and Rehabilitation (1%). Admissions for this study were grouped into both the larger MSOA and smaller Lower Super Output Areas (LSOA), both of which are statistical geographies used in England. At that time the importance of the 2010 event was not appreciated [18,19], and hence this study also seeks to clarify the nature of this event.

No patient identifiable data was used, and a previously prepared extract at LSOA level [4] was analyzed. Admissions for persons living outside of Wigan were aggregated at local authority level or into larger geographies. Daily admissions for each MSOA/LSOA/area were summed into running 365 day totals. As in previous studies [19-25] the size of any step-like change is calculated by comparing the magnitude of the step-up and step-down associated with each event. This was determined using differences between successive running 365 day totals. Hence the first successive difference starts with a comparison of the running 365 day total ending 31st March 2009, with the running total ending 31st March 2010 as a percentage difference between the two periods. This detects any step-change occurring at 31st March 2009, move forward one day and repeat the comparison. Points of maximum and minimum percentage difference then identify the respective step-up and step-down events.

Monthly deaths (all-cause mortality) for the residents of Wigan were obtained from the Office for National Statistics. Data on the population density (persons/hectare), Index of Multiple Deprivation (IMD), which ranges from 0 (least deprived) through to 100 (most deprived), social classification (using the output area classification methodology), and proportion of persons aged 70+, were all obtained from the Office for National Statistics.

Statistical analysis is based on Poisson statistics where, by definition, the standard deviation is equal to the square root of the average. This square root relationship with the average attenuates the effect of uncertainty in the average. This study uses two measures of the average. In the evaluation of the maximum step-change over the entire period, the average was calculated over the full time period April-08 to May-12. For the evaluation of the 2009/10 event, the average was calculated over the interval specific to this event, namely, Mar-09 to Feb-11.

The relationship between the standard deviation of a Poisson distribution and the square root of the average can also be used to convert percentage increases in medical admissions in different sized LSOA (as average number of admissions) into standard deviation (STDEV) equivalents. Hence a 10% increase observed in a LSOA with an average of 100 admissions is equivalent to a 1 STDEV equivalent increase, etc.

Results

This study uses both MSOA and LSOA small areas within Wigan. Each MSOA contains three to eight LSOA with four to five being the most common. Each LSOA contains an average of 1,500 persons (range 1,000 to 3,000 persons, or 400 to 1,200 households). Hence this study is investigating very small spatial areas.

A running 365 day or 12 month total is a useful tool for detecting step-like changes in admission rates or deaths when the admissions/deaths show high seasonality [32-34], while the use of a larger running total minimizes the contribution from Poisson randomness, and effectively de-seasonalizes the trend [35]. A step-like increase, when analyzed using a running total, results in a ramp where the foot of the ramp marks the onset of the step-change, the slope of the ramp indicates the magnitude of the step-change, and the point 365 days or 12 months after the onset also reflects the size of the step-change (assuming the event has endured for a full 365 days).

Step-changes in deaths

To set the context for this paper, Figure 1 shows a running 12 month total of deaths for the 12 month period ending Dec-06 to May-15. According to the Office for National Statistics in the 2008-based components of change, deaths in Wigan were supposed to decline along a continuous line with around 3,100 deaths in 2009 reducing to 2,900 deaths in 2015[36]. The peaks and troughs in Figure 1 (as seen in all other local authorities across the UK) are therefore entirely unexpected and have never been given an official explanation [15,18]. Figure 1 therefore shows a series of step-like increasesin deaths commencing somewhere around May-07 (+8.7%), Feb-10 (+5.4%, less prominent perhaps due to slower and more granular spread), Apr-12 (+7.7%) and May-14 (+8.8%). Each peak may be made up from spatial spread within Wigan, and the remainder of this paper will investigate the accompanying small-area effect on medical admissions. It has been estimated that for every death there are around 10 extra medical admissions, although this ratio seems to vary between the events [37,38]. Note that background scatter of up to ±50 will arise due to Poisson variation and this explains most of the smaller saw-tooth features in Figure 1. The duration of this study does not cover the 2014/15 event although timing for initiation at Local Authority level across England has been presented elsewhere [19].

It has also been observed that deaths lag behind admissions and emergency department attendances by around one to two months [25,39], i.e. initial illness and decline precede eventual death. Hence the timing of small area events using medical admissions may occur earlier than seen for deaths in Figure 1.

Step changes in admissions

It is commonly believed throughout the health services in the UK, that population demographic change is the principle driving force for the increase in medical (and other) admissions [40], and an increasingly elderly population in Wigan would imply that the minimum number of admissions should occur toward the start of the study period and the maximum toward the end. This is totally at variance for the wide range in dates for the maximum and minimum admissions demonstrated in Table S1 in the supplementary material. Indeed the point of maximum 365 day total admissions can range anywhere between 31st Mar 2009 through to 31st March 2013 (Wigan 011C versus Wigan 032A), as can the point of minimum admissions (Wigan 020A versus Wigan 012C). Typical winter infectious events are assumed to have only a small effect on the overall trend. The available data used in this study encompasses the tail end of the 2007/08 event, the full range of the 2010/11 event and the leading edge of the 2012/13 event, i.e. there are a maximum of three possible maxima and three possible minima during this period [19], as in Figure 1.

Table S1: Details for the 100 largest areas/LSOA used in this study

Location or LSOA

Average admissions

Maximum admissions

Minimum admissions

Range as percentage of average

Running 365 day Maximum

Running 365 day Minimum

Max-Min (years)

Maximum Step-Increase

Maximum Step-Decrease

± 1 Standard Deviation (Poisson)

Start of largest step-increase

All locations

19,420

20,436

18,313

11%

29-Sep-10

31-Jan-12

-1.3

4%

9%

1%

31-Jan-12

Wigan

17,291

18,194

16,342

11%

29-Sep-10

31-Jan-12

-1.3

4%

9%

1%

13-Nov-11

Not Wigan

2,129

2,286

1,937

16%

29-Sep-10

31-Jan-12

-1.3

14%

15%

2%

01-Jun-09

W. Lancashire

672

718

605

17%

14-Jan-13

07-Feb-12

0.9

18%

14%

4%

15-Jan-12

Unknown

654

737

462

42%

07-Apr-11

03-Apr-09

2.0

39%

13%

4%

13-Jun-09

Wigan 031E

333

385

259

38%

14-Jan-11

04-Feb-12

-1.1

41%

31%

5%

04-Feb-12

St. Helens

293

336

252

29%

20-Jul-09

01-Mar-11

-1.6

20%

23%

6%

22-Apr-11

Wigan 015D

256

345

197

58%

16-Jan-10

08-Jul-12

-2.5

17%

35%

6%

20-Mar-12

Other UK

241

303

171

55%

06-Nov-09

24-Jul-12

-2.7

10%

31%

6%

30-Mar-12

Wigan 009C

224

277

189

39%

09-Feb-10

24-Feb-12

-2.0

12%

22%

7%

11-Apr-09

Wigan 035A

205

245

159

42%

18-May-11

11-Jun-10

0.9

48%

29%

7%

11-Jun-10

Wigan 010C

196

248

175

37%

19-Jul-09

26-Nov-10

-1.4

15%

25%

7%

26-Nov-10

Wigan 014B

193

222

163

31%

22-Oct-10

12-Sep-11

-0.9

34%

25%

7%

18-Mar-12

Wigan 033E

190

241

150

48%

18-Apr-09

21-Dec-11

-2.7

40%

23%

7%

21-Dec-11

Wigan 015B

186

221

153

37%

27-Apr-11

28-Jul-10

0.7

43%

26%

7%

28-Feb-10

Wigan 016E

174

200

137

36%

23-Apr-11

25-Jan-13

-1.8

23%

28%

8%

04-Apr-09

Wigan 032D

167

204

131

44%

13-Oct-10

22-Mar-13

-2.4

31%

30%

8%

20-Jun-09

Wigan 015C

166

192

142

30%

30-Jun-11

11-Jan-10

1.5

25%

19%

8%

12-Jan-10

Wigan 010D

163

223

114

67%

12-Nov-10

11-Apr-09

1.6

77%

43%

8%

16-Nov-09

Wigan 009A

162

195

132

39%

14-Aug-10

21-Jun-12

-1.9

23%

28%

8%

19-Jun-09

Wigan 012B

159

176

134

26%

06-Jun-09

17-Sep-12

-3.3

14%

16%

8%

13-Feb-11

Wigan 015E

156

190

127

40%

24-Aug-09

05-Dec-12

-3.3

9%

23%

8%

03-Apr-09

Wigan 012C

156

182

132

32%

09-Nov-09

31-Mar-13

-3.4

21%

23%

8%

05-Jan-11

Wigan 010B

153

191

130

40%

07-Jun-10

02-Jun-12

-2.0

36%

30%

8%

16-May-09

Wigan 013C

152

181

106

49%

26-Feb-10

16-Dec-11

-1.8

44%

39%

8%

28-Dec-11

Wigan 036C

152

175

128

31%

24-May-12

14-May-10

2.0

26%

23%

8%

20-Mar-10

Wigan 024B

150

184

118

44%

24-May-09

26-Sep-11

-2.3

27%

33%

8%

22-Aug-11

Wigan 027D

148

170

119

34%

09-Dec-09

08-Dec-12

-3.0

24%

27%

8%

20-Sep-10

Wigan 012D

147

198

96

69%

26-May-09

28-Nov-12

-3.5

5%

36%

8%

29-Nov-10

Wigan 010A

143

168

121

33%

02-Aug-09

26-Jan-13

-3.5

16%

21%

8%

04-Jul-10

Wigan (small)

143

170

125

31%

27-Nov-09

13-Sep-12

-2.8

17%

24%

8%

08-Jun-09

Wigan 036A

142

175

114

43%

16-Jun-12

31-Oct-10

1.6

32%

20%

8%

07-Nov-10

Wigan 016A

141

161

111

35%

13-Dec-09

23-Oct-12

-2.9

14%

26%

8%

29-Apr-09

Wigan 040D

140

189

101

63%

21-Nov-12

31-Mar-09

3.6

55%

23%

8%

27-Dec-11

Wigan 007B

140

169

105

46%

03-Sep-09

22-Apr-12

-2.6

23%

37%

8%

09-Jul-10

Wigan 012A

140

182

100

59%

17-Sep-10

08-Jan-13

-2.3

33%

36%

8%

14-Sep-09

Wigan 006B

137

157

115

31%

26-Dec-09

23-Mar-12

-2.2

33%

20%

9%

28-Mar-12

Wigan 013B

134

159

104

41%

09-Jun-10

04-Jun-12

-2.0

46%

23%

9%

26-Mar-12

Wigan 008C

133

163

114

37%

24-Oct-10

03-Apr-09

1.6

38%

28%

9%

19-Sep-09

Bolton

132

162

104

44%

11-Feb-12

10-Apr-11

0.8

49%

25%

9%

13-Apr-11

Wigan 038D

130

144

107

28%

30-Oct-10

12-Mar-13

-2.4

19%

21%

9%

21-Oct-09

Wigan 009B

129

144

108

28%

18-Jan-11

04-Apr-12

-1.2

13%

24%

9%

17-Aug-10

Wigan 024C

128

143

111

25%

15-Oct-10

07-Apr-09

1.5

22%

18%

9%

13-Oct-09

Wigan 027A

127

165

85

63%

17-Dec-09

06-Nov-12

-2.9

18%

38%

9%

30-Mar-12

Wigan 036B

127

149

100

39%

11-May-10

17-May-12

-2.0

29%

28%

9%

26-Oct-09

Wigan 002A

126

152

98

43%

11-Sep-10

05-Nov-12

-2.2

13%

24%

9%

12-Sep-09

Wigan 009D

126

204

95

87%

13-Dec-12

04-Jun-09

3.5

95%

17%

9%

04-Jun-09

Wigan 005B

124

149

98

41%

25-Aug-10

06-Sep-09

1.0

52%

22%

9%

06-Sep-09

Wigan 016B

123

160

90

57%

10-Feb-12

31-Mar-09

2.9

31%

34%

9%

10-Feb-11

Wigan 010E

123

161

106

45%

09-May-09

13-May-12

-3.0

14%

29%

9%

08-Jan-10

Wigan 018B

119

141

93

40%

19-Jul-11

16-Jul-12

-1.0

30%

34%

9%

12-May-10

Wigan 014D

119

139

103

30%

02-Apr-09

11-Feb-12

-2.9

26%

19%

9%

11-Feb-12

Wigan 002E

118

143

98

38%

01-Apr-09

25-Jan-12

-2.8

27%

22%

9%

07-Feb-12

Wigan 009E

117

128

98

26%

19-Jan-10

20-Nov-10

-0.8

21%

23%

9%

20-Nov-10

Wigan 013A

116

133

89

38%

02-Sep-11

04-Jun-10

1.2

40%

31%

9%

01-Aug-10

Wigan 005E

115

130

101

25%

23-Aug-10

11-Nov-11

-1.2

18%

22%

9%

11-Jul-11

Wigan 019C

115

136

97

34%

23-Jan-11

12-Apr-12

-1.2

21%

27%

9%

23-Jan-10

Wigan 024A

115

136

97

34%

04-Jan-10

07-Jun-11

-1.4

26%

24%

9%

07-Jun-11

Wigan 011E

113

135

86

43%

17-Jan-11

15-Feb-13

-2.1

13%

32%

9%

03-Jun-10

Wigan 008B

113

136

95

36%

12-Sep-11

09-Mar-13

-1.5

33%

27%

9%

22-Mar-10

Wigan 016C

113

137

96

36%

20-Oct-09

18-Jul-12

-2.7

17%

22%

9%

25-Jan-11

Wigan 027C

112

137

89

43%

11-Apr-09

22-Nov-10

-1.6

31%

27%

9%

03-Aug-11

Wigan 006E

109

133

85

44%

02-Mar-11

23-Dec-11

-0.8

40%

35%

10%

23-May-10

Wigan 004D

109

127

90

34%

10-Apr-11

09-Apr-12

-1.0

30%

29%

10%

10-Apr-10

Wigan 018C

108

126

98

26%

20-Jul-11

03-Aug-10

1.0

27%

18%

10%

20-Jul-10

Wigan 015A

108

149

83

61%

29-Mar-10

22-Apr-11

-1.1

42%

43%

10%

09-Apr-09

Wigan 006A

107

136

77

55%

18-Jan-10

19-Feb-13

-3.1

34%

34%

10%

30-Aug-11

Wigan 014A

105

125

84

39%

13-Jul-10

13-Jul-11

-1.0

37%

33%

10%

13-Jul-11

Wigan 003D

104

151

66

82%

14-Dec-10

16-Dec-11

-1.0

54%

56%

10%

06-Oct-09

Wigan 011B

104

141

83

56%

10-Mar-13

03-Apr-12

0.9

63%

26%

10%

16-Mar-12

Wigan 026E

104

140

67

70%

30-Mar-10

26-Feb-13

-2.9

58%

34%

10%

31-Mar-09

Wigan 020C

103

137

76

59%

13-Sep-10

03-Aug-12

-1.9

57%

32%

10%

16-Sep-09

Wigan 005A

102

120

84

35%

22-Dec-10

28-Dec-09

1.0

43%

23%

10%

28-Dec-09

Wigan 001C

101

118

86

32%

19-Jan-11

01-Jun-10

0.6

31%

23%

10%

03-Mar-10

Wigan 011A

101

118

82

36%

21-Jun-10

14-Nov-12

-2.4

23%

29%

10%

04-Jul-11

Wigan 030B

99

122

74

48%

25-Aug-10

19-Oct-11

-1.2

49%

37%

10%

23-Nov-11

Wigan 033B

99

119

79

40%

28-Jan-10

30-Mar-13

-3.2

21%

22%

10%

02-Aug-11

Wigan 002C

98

120

74

47%

18-Feb-11

23-Jun-09

1.7

34%

24%

10%

13-Feb-10

Wigan 011C

98

133

78

56%

31-Mar-09

19-Dec-11

-2.7

41%

40%

10%

25-Apr-10

Wigan 007D

97

126

72

55%

03-Jul-10

20-Aug-11

-1.1

40%

38%

10%

05-Oct-11

Wigan 018E

97

114

84

31%

18-Oct-12

07-Apr-09

3.5

33%

21%

10%

19-Oct-11

Wigan 019A

96

113

69

46%

18-Sep-12

07-Nov-10

1.9

62%

32%

10%

10-Nov-10

Wigan 013D

94

122

68

57%

09-Apr-09

09-Jul-10

-1.2

63%

42%

10%

10-Jul-10

Wigan 038E

93

114

69

48%

28-Jan-11

04-Jul-09

1.6

48%

32%

10%

05-Feb-10

Wigan 038C

93

115

74

44%

16-May-11

06-Jan-10

1.4

52%

28%

10%

13-Feb-10

Wigan 032C

92

112

68

48%

28-Aug-12

13-May-09

3.3

31%

19%

10%

13-May-09

Wigan 020A

92

103

75

30%

26-Feb-10

31-Mar-09

0.9

37%

20%

10%

01-Apr-09

Wigan 033D

92

113

61

57%

22-Feb-13

03-Apr-09

3.9

56%

30%

10%

25-Jun-09

Wigan 027B

92

109

70

43%

21-Jun-11

08-Apr-10

1.2

51%

22%

10%

08-Apr-10

Wigan 012E

92

110

76

37%

07-Jun-11

04-Mar-13

-1.7

26%

23%

10%

15-Jun-10

Wigan 024D

91

100

80

22%

05-May-11

05-May-10

1.0

25%

16%

11%

30-May-10

Wigan 014C

88

121

65

63%

23-Dec-10

19-Jul-09

1.4

82%

41%

11%

13-Oct-09

Wigan 026D

88

103

73

34%

23-Oct-09

21-Dec-11

-2.2

41%

20%

11%

21-Dec-11

Wigan 032A

88

108

73

40%

31-Mar-13

22-Jan-11

2.2

33%

24%

11%

23-Apr-11

Wigan 032E

87

103

67

41%

05-Jun-11

04-Apr-09

2.2

37%

24%

11%

04-Apr-09

Wigan 031A

86

126

63

73%

05-Mar-11

06-Mar-10

1.0

100%

39%

11%

06-Mar-10

Wigan 018A

86

123

65

68%

14-Jul-11

29-Nov-09

1.6

68%

46%

11%

20-Jun-10

Wigan 014E

85

107

67

47%

28-Nov-12

25-Sep-10

2.2

37%

26%

11%

01-Dec-11

Wigan 037B

85

106

63

51%

30-Nov-10

29-Nov-11

-1.0

50%

40%

11%

03-Jan-12

Wigan 026C

83

109

66

52%

21-Aug-10

11-Sep-12

-2.1

50%

35%

11%

08-Apr-09

 

 

 

 

 

 

 

 

 

 

 

Admissions for residents in nearby West Lancashire displays three peaks of roughly similar magnitude for the 365 days ending 16th July 2009, 3rd March 2011 and 14th January 2013. For the residents of Wigan the tail of the 2008 event appears to merge with the start of the 2010 event giving an initial plateau around 17,650 admissions per 365 days, then a peak of 18,194 admissions for the 365 days ending 29th September 2010, followed by a minimum of 16,342 for the 365 days ending 31st January 2012 and then a maximum of 17,029 for the 365 days ending 12th November 2012 (data not shown).

However, as can be seen in Figure 2 the small-area trends display considerable variation between LSOA in Wigan. Such disparate trends are difficult to explain from an assumed demographic perspective, since all should be showing roughly linear trends with a slight upward slope of around 1% to 2% per annum. Hence as in Figure1 there are a series of trends without any apparent explanation and which seem to defy commonly held notions regarding demographic growth as the principle driving force for change.

The initial plateau for Wigan as a whole, and Wigan 013C may illustrate the one weakness in the running 365 day approach in that an unexpected ‘spike’ event (arising from a typical temporary infectious outbreak such as influenza, SARS, or an extreme of temperature) creates a flat-topped plateau-like feature as the spike moves its way along the running 365 day total. The shape of the earlier part of the trend for Wigan 013C suggests such a spike event may be acting to obscure other trends, however, while the step-up may have been obscured, the step-down (as a ramp) is clearly visible. While it is far easier to adjust for spike events using monthly data (see [41] as an example), it is more difficult to do this in a running 365 day total, and it is exactly for this reason that this study uses both the step-up and step-down parts of the events, and for simplicity, this part of the analysis only documents the largest event in each small area. Hence using Figure 1as an example the largest step-down would have occurred at the cessation of the 2007/08 event, etc.

Figure 1. Running 12 month total of deaths (all-cause mortality) for residents of Wigan, near Manchester (UK) - this time-series covers four outbreaks of the suspected new agent

Step-like increases in admissions (generating an upward ramp in a running 365 day total chart) can be seen, as are step-like reductions (a ramp downward) following the cessation of an event. The upward ramps are not perfectly linear simply because spread of the agent throughout each LSOA is not instantaneous. Wigan 011C appears to show only the step-down following the 2007/08 event while Wigan 011B only appears to show a strong step-up for the 2012/13 event (the time span of the study limiting the ability to detect the ensuing step-down). As can be appreciated, the spatiotemporal trend for the whole of Wigan is a composite of all the smaller areas, and there appears to be considerable granularity/heterogeneity in the spread of the agent.

Table S1 in the Supplementary material presents summary data for the 100 largest LSOA. Note the large percentage difference between the maximum and minimum running annual total for admissions, which is far beyond anything arising from chance, and the wide variation in the dates for the maximum and minimum admissions, and the onset of the step-up and step-down features. Clearly something far more powerful than demographic-driven change is occurring and complex spatiotemporal effects are hidden in the larger geographic areas.

Magnitude of the maximum step-up or step-down

While the use of daily admissions generates more complex trends than those observed in earlier studies using monthly admissions, it is still possible to calculate the size of any step-like changes by comparing the percentage difference between successive 365 day blocks of data each side of a step-like change, for example, 365 days ending December 2012 compared to December 2011. Figure 3 shows the size of the largest step-like increase in each LSOA and MSOA (or other geography), and the size of the largest step-like decrease which will occur following the cessation of such an event. Both step-up and step-down have been calculated relative to the average number of admissions to avoid the situation where the step-down appears smaller by virtue of comparison against the larger total admissions after the start of the event. Figure 3 also shows the range between the maximum and minimum running 365 day total of admissions expressed as a percentage of the average admissions. As expected the range is slightly higher than the maximum step-up or step-down simply because it encompasses the sum of all possible effects against admissions during the time of the study. However the value of the range is not widely different to the step-up and step-down values, indicating that these step-like changes are the principle factor regulating changes in admissions.

Figure 2. Range in running 365 day total medical admissions for a selection of Wigan statistical geographies called lower super output areas (LSOA)

Figure 3. Value of the maximum percentage increase in admissions due to a step-like increase, the maximum step-like reduction after the cessation of the infectious-like events, and the range between maximum and minimum admissions in each LSOA or other area

As can be seen, the value for the largest step-up or step-down are roughly similar except at the extreme points measured across the entire hospital catchment area, or for the whole of Wigan. Also that the step-like changes are mostly greater than the value of a +1 standard deviation (SD) change which could arise from simple Poisson variation. As expected, potential Poisson variation increases with decreasing size since, by definition, the standard deviation of a Poisson distribution is equal to the square root of the average. In a Poisson distribution the + 1 standard deviation line encompasses 85% of all possible outcomes arising from chance, and effectively represents the 85% confidence interval, i.e. in a Poisson distribution, 85% of all data values are expected to lie below the + 1SD line – which is clearly not the case.

The value of the power function in the trend lines in Figure 3 range from -0.332 for step-down to -0.444 for step-up. It is possible that the value of the exponent has been reduced by the high data points at whole hospital and Wigan level. However these values are not too different from a value of -0.5 expected from a pure Poisson function, which indicates that Poisson chance events may form a basis for the mechanisms behind these events.

The value of ± 1 standard deviation (Poisson) can be used to determine the potential contribution from chance variation to each calculated increase. As can also be seen in Figure 3, the step-up in just four LSOA fails to exceed the 85% CI (Poisson), however, in all cases the maximum step-down is higher.

Table S2 in the supplementary material summarizes the details for the all the LSOA within the MSOAs in Wigan along with admissions from other areas. Note how the step-up or step–down is usually lower at MSOA level, and this is due to the wide variation in initiation dates for the step-up or step–down events, i.e. slow spatial spread within the geography of a single MSOA is leading to a degree of cancelling-out between the rectangular wave events which obscures the full extent of the effect seen at the smaller geographies. There are occasional exceptions to this rule and the maximum step-change in Wigan 022D is lower than that observed for Wigan 022. This is simply an expression of the high granularity/heterogeneity associated with these events.

Table S2: Details of the largest step-u and step-down, plus the 2009/10 event for MSOA and associated LSOA within each of these MSOA

Location

Admissions per 365 days

Largest step-up or step-down

2009/10 Event

Maximum

Minimum

Average (Apr-08 to May-12)

Average (Mar-09 to Feb-11)

Range (max - min)

Step-up

Step-down

85% CI (Poisson)

Start Up

Start Down

Differ-ence (years)

Ratio Max up/down

Start of event

Average Step-change

Adjusted to 100 deaths equivalent

All areas

20,436

18,313

19,420

19,947

11%

4%

10%

1%

31-Jan-12

23-Oct-10

-1.3

37%

29-Sep-09

6%

89%

Wigan

18,194

16,342

17,291

17,769

11%

3%

10%

1%

13-Nov-11

23-Oct-10

-1.1

36%

29-Sep-09

6%

85%

Not Wigan

2,286

1,937

2,129

2,179

16%

13%

16%

2%

1-Jun-09

28-Mar-11

1.8

79%

28-Mar-10

10%

48%

W. Lancashire

718

605

672

686

17%

16%

15%

4%

15-Jan-12

19-Feb-11

-0.9

107%

3-Mar-10

10%

26%

Unknown

737

462

654

618

42%

29%

15%

4%

13-Jun-09

8-Apr-11

1.8

193%

7-Apr-10

15%

39%

Bolton

162

104

132

127

44%

39%

30%

9%

13-Apr-11

28-Jan-12

0.8

128%

10-Apr-09

9%

11%

Chorley

69

36

53

58

62%

43%

55%

14%

11-Jun-11

11-Feb-10

-1.3

79%

10-May-09

26%

19%

Other

303

171

241

278

55%

11%

33%

6%

30-Mar-12

20-Jun-11

-0.8

34%

25-Jun-09

14%

22%

St. Helens

336

252

293

305

29%

17%

25%

6%

22-Apr-11

1-Mar-10

-1.1

68%

8-Apr-09

9%

15%

Warrington

45

12

30

37

110%

56%

56%

18%

12-Apr-09

20-Dec-11

2.7

100%

23-Apr-09

53%

29%

Wigan (small)

170

125

143

147

31%

15%

28%

8%

8-Jun-09

28-Nov-09

0.5

55%

13-Jul-09

15%

18%

Wigan 001A

109

54

72

81

76%

65%

68%

12%

17-Oct-09

17-Oct-10

1.0

96%

17-Oct-09

66%

56%

Wigan 001B

74

34

56

66

71%

50%

52%

13%

3-Mar-12

26-Feb-11

-1.0

97%

1-Apr-09

23%

17%

Wigan 001C

118

86

101

100

32%

28%

25%

10%

3-Mar-10

1-Jun-09

-0.8

112%

3-Mar-10

25%

25%

Wigan 001D

57

29

41

36

68%

51%

51%

16%

19-Jul-10

23-Dec-11

1.4

100%

18-May-10

34%

22%

Wigan01

325

235

270

282

33%

24%

30%

6%

16-Oct-09

23-Oct-10

1.0

79%

23-Oct-09

27%

45%

Wigan 002A

152

98

126

138

43%

14%

28%

9%

12-Sep-09

28-Nov-10

1.2

50%

28-Nov-09

19%

21%

Wigan 002B

76

48

62

64

45%

35%

45%

13%

1-Oct-09

7-Oct-10

1.0

79%

1-Oct-09

39%

31%

Wigan 002C

120

74

98

93

47%

31%

30%

10%

13-Feb-10

18-Feb-11

1.0

103%

18-Feb-10

30%

30%

Wigan 002D

76

40

52

48

70%

66%

21%

14%

1-Nov-11

3-Oct-10

-1.1

309%

3-Oct-09

16%

12%

Wigan 002E

143

98

118

124

38%

22%

24%

9%

7-Feb-12

5-Feb-11

-1.0

93%

5-Feb-10

16%

18%

Wigan02

502

401

457

467

22%

19%

20%

5%

21-Feb-12

23-Feb-11

-1.0

97%

25-Feb-10

15%

32%

Wigan 003A

91

60

76

82

41%

20%

32%

11%

29-Dec-11

1-Mar-10

-1.8

63%

24-May-09

22%

19%

Wigan 003B

98

56

78

88

54%

30%

36%

11%

11-Feb-12

6-Sep-10

-1.4

82%

6-Sep-09

20%

18%

Wigan 003C

96

61

76

78

46%

22%

46%

11%

12-Oct-10

11-Oct-09

-1.0

49%

11-May-10

8%

7%

Wigan 003D

151

66

104

119

82%

50%

82%

10%

6-Oct-09

15-Dec-10

1.2

61%

17-Dec-09

65%

67%

Wigan 003E

98

64

77

81

44%

25%

34%

11%

22-Feb-11

10-Oct-09

-1.4

73%

1-Apr-09

8%

7%

Wigan 003F

68

33

47

39

75%

47%

19%

15%

22-Aug-10

31-Mar-09

-1.4

244%

28-Feb-10

18%

12%

Wigan 003G

80

26

58

72

94%

33%

74%

13%

14-Mar-12

15-Jun-11

-0.7

44%

12-Nov-09

44%

34%

Wigan03

584

430

516

559

30%

11%

26%

4%

11-Dec-11

14-Dec-10

-1.0

44%

14-Dec-09

14%

31%

Wigan 004A

101

58

78

67

55%

47%

15%

11%

3-Nov-10

27-Feb-12

1.3

308%

13-Jun-10

20%

18%

Wigan 004B

101

60

81

82

51%

28%

49%

11%

9-Jan-12

1-Dec-09

-2.1

58%

24-May-10

7%

6%

Wigan 004C

99

59

77

71

52%

47%

35%

11%

3-Mar-11

30-Mar-12

1.1

133%

31-Mar-09

18%

16%

Wigan 004D

127

90

109

109

34%

27%

34%

10%

10-Apr-10

10-Apr-11

1.0

78%

10-Apr-10

30%

32%

Wigan04

389

302

345

329

25%

21%

18%

5%

3-Nov-10

12-Jul-09

-1.3

121%

29-Apr-10

6%

11%

Wigan 005A

120

84

102

103

35%

35%

27%

10%

28-Dec-09

28-Dec-10

1.0

133%

28-Dec-09

31%

31%

Wigan 005B

149

98

124

122

41%

41%

27%

9%

6-Sep-09

4-Sep-10

1.0

155%

4-Sep-09

33%

37%

Wigan 005C

92

60

74

76

43%

34%

42%

12%

29-Mar-12

5-Jul-09

-2.7

81%

5-Apr-10

17%

15%

Wigan 005D

96

43

75

77

71%

48%

61%

12%

6-Sep-09

27-Feb-12

2.5

78%

31-Dec-09

28%

24%

Wigan 005E

130

101

115

119

25%

17%

24%

9%

11-Jul-11

27-Aug-10

-0.9

68%

30-Aug-09

20%

21%

Wigan05

552

452

490

498

20%

17%

15%

5%

29-Dec-09

19-Sep-10

0.7

109%

17-Sep-09

16%

35%

Wigan 006A

136

77

107

122

55%

25%

38%

10%

30-Aug-11

15-Sep-10

-1.0

66%

25-Jul-09

16%

17%

Wigan 006B

157

115

137

141

31%

28%

22%

9%

28-Mar-12

29-May-10

-1.8

127%

1-Jun-09

20%

24%

Wigan 006C

98

42

69

80

81%

45%

55%

12%

30-Sep-09

20-Oct-10

1.1

82%

5-Oct-09

47%

39%

Wigan 006D

102

47

76

85

73%

53%

49%

11%

17-Feb-12

4-Jan-11

-1.1

108%

4-Jan-10

26%

23%

Wigan 006E

133

85

109

113

44%

33%

42%

10%

23-May-10

23-Dec-10

0.6

78%

23-Dec-09

34%

35%

Wigan06

564

413

498

541

30%

12%

26%

4%

2-Jan-12

7-Jan-11

-1.0

47%

16-Sep-09

14%

32%

Wigan 007A

89

52

70

69

53%

45%

32%

12%

26-Aug-11

25-Aug-10

-1.0

141%

18-May-09

24%

20%

Wigan 007B

169

105

140

152

46%

21%

44%

8%

9-Jul-10

19-Mar-11

0.7

48%

19-Mar-10

29%

35%

Wigan 007C

59

28

42

47

74%

14%

40%

15%

1-Dec-11

30-Jan-11

-0.8

35%

6-Mar-10

23%

15%

Wigan 007D

126

72

97

109

55%

30%

48%

10%

5-Oct-11

20-Aug-10

-1.1

62%

4-Jul-09

36%

36%

Wigan007

398

281

349

378

34%

19%

27%

5%

2-Dec-11

2-Dec-10

-1.0

72%

4-Jan-10

13%

24%

Wigan 008A

90

57

74

80

44%

13%

24%

12%

10-Aug-09

30-Nov-09

0.3

56%

10-Aug-09

17%

15%

Wigan 008B

136

95

113

112

36%

28%

32%

9%

22-Mar-10

20-Sep-11

1.5

89%

18-Feb-10

24%

26%

Wigan 008C

163

114

133

136

37%

34%

35%

9%

19-Sep-09

22-Oct-10

1.1

98%

27-Oct-09

33%

38%

Wigan 008D

91

62

76

77

38%

34%

29%

11%

6-Sep-11

18-May-10

-1.3

118%

2-Oct-09

21%

18%

Wigan 008E

92

52

70

71

57%

53%

38%

12%

16-Nov-09

3-Sep-11

1.8

137%

11-Apr-10

41%

35%

Wigan008

528

434

467

476

20%

19%

17%

5%

5-Nov-09

22-Dec-10

1.1

113%

2-Nov-09

17%

37%

Wigan 009A

195

132

162

174

39%

22%

34%

8%

19-Jun-09

16-Aug-10

1.2

64%

16-Aug-09

27%

35%

Wigan 009B

144

108

129

132

28%

12%

26%

9%

17-Aug-10

5-Apr-11

0.6

47%

5-Apr-10

19%

21%

Wigan 009C

277

189

224

244

39%

13%

26%

7%

11-Apr-09

22-Apr-10

1.0

47%

22-Apr-09

19%

28%

Wigan 009D

204

63

126

97

112%

68%

16%

9%

4-Jun-09

17-Mar-10

0.8

430%

25-May-09

31%

35%

Wigan 009E

128

98

117

114

26%

18%

25%

9%

20-Nov-10

20-Nov-09

-1.0

72%

21-May-10

6%

6%

Wigan009

810

699

756

761

15%

14%

9%

4%

19-Jan-12

24-Mar-10

-1.8

146%

27-May-09

10%

27%

Wigan 010A

168

121

143

148

33%

15%

24%

8%

4-Jul-10

4-Aug-09

-0.9

60%

17-May-10

7%

8%

Wigan 010B

191

130

153

169

40%

33%

38%

8%

16-May-09

11-Jun-10

1.1

86%

7-Jun-09

33%

41%

Wigan 010C

248

175

196

204

37%

13%

32%

7%

26-Nov-10

2-Aug-09

-1.3

42%

30-Jan-10

8%

12%

Wigan 010D

223

114

163

165

67%

59%

56%

8%

16-Nov-09

8-Jan-11

1.1

105%

12-Nov-09

57%

73%

Wigan 010E

161

106

123

132

45%

13%

38%

9%

8-Jan-10

16-May-09

-0.6

35%

8-Jan-10

15%

16%

Wigan010

863

703

778

818

21%

12%

19%

4%

27-Dec-09

11-Jan-11

1.0

66%

8-Jan-10

15%

43%

Wigan 011A

118

82

101

109

36%

19%

34%

10%

4-Jul-11

28-Jun-10

-1.0

56%

21-Jun-09

22%

22%

Wigan 011B

141

83

104

104

56%

52%

31%

10%

16-Mar-12

22-Jan-10

-2.1

169%

13-Sep-09

13%

13%

Wigan 011C

133

78

98

101

56%

33%

54%

10%

25-Apr-10

31-Mar-09

-1.1

60%

22-Mar-10

32%

31%

Wigan 011D

78

58

66

68

30%

15%

23%

12%

3-Jul-10

21-Jun-09

-1.0

67%

31-May-10

11%

9%

Wigan 011E

135

86

113

122

43%

13%

37%

9%

3-Jun-10

7-Jan-11

0.6

36%

11-Jan-10

23%

25%

Wigan011

527

419

482

504

22%

13%

18%

5%

16-Mar-12

25-Dec-10

-1.2

75%

25-Apr-10

10%

22%

Wigan 012A

182

100

140

159

59%

32%

46%

8%

14-Sep-09

6-Nov-10

1.1

70%

8-Oct-09

38%

44%

Wigan 012B

176

134

159

166

26%

13%

18%

8%

13-Feb-11

13-Feb-10

-1.0

75%

14-Sep-09

10%

13%

Wigan 012C

182

132

156

159

32%

19%

26%

8%

5-Jan-11

9-Nov-09

-1.2

71%

13-Apr-09

11%

13%

Wigan 012D

198

96

147

170

69%

5%

39%

8%

29-Nov-10

29-Nov-11

1.0

12%

20-May-10

6%

7%

Wigan 012E

110

76

92

91

37%

25%

26%

10%

15-Jun-10

10-Mar-12

1.7

96%

7-Jun-10

25%

24%

Wigan012

801

570

694

745

33%

6%

17%

4%

11-Apr-09

9-Jan-12

2.7

33%

1-Apr-09

9%

23%

Wigan 013A

133

89

116

108

38%

33%

35%

9%

1-Aug-10

4-Jun-09

-1.2

95%

13-May-10

13%

14%

Wigan 013B

159

104

134

140

41%

37%

23%

9%

26-Mar-12

5-Jun-11

-0.8

161%

9-Jun-09

23%

27%

Wigan 013C

181

106

152

172

49%

31%

45%

8%

28-Dec-11

10-Dec-10

-1.0

68%

3-Dec-09

29%

35%

Wigan 013D

122

68

94

92

57%

46%

53%

10%

10-Jul-10

9-Jul-09

-1.0

86%

8-Jun-10

30%

29%

Wigan 013E

81

52

65

68

45%

23%

35%

12%

26-Jun-11

26-Jul-10

-0.9

65%

26-Jul-09

24%

19%

Wigan013

628

507

561

579

22%

9%

13%

4%

24-Mar-12

9-Apr-09

-3.0

67%

23-Apr-10

7%

17%

Wigan 014A

125

84

105

111

39%

30%

39%

10%

13-Jul-11

13-Jul-10

-1.0

76%

19-Oct-09

32%

33%

Wigan 014B

222

163

193

203

31%

29%

28%

7%

18-Mar-12

12-Sep-10

-1.5

102%

27-Dec-09

19%

26%

Wigan 014C

121

65

88

90

63%

60%

52%

11%

13-Oct-09

14-Apr-11

1.5

115%

23-Dec-09

49%

46%

Wigan 014D

139

103

119

120

30%

23%

22%

9%

11-Feb-12

31-Mar-08

-3.9

104%

13-Sep-09

13%

14%

Wigan 014E

107

67

85

81

47%

34%

28%

11%

1-Dec-11

19-Oct-09

-2.1

121%

18-May-09

7%

7%

Wigan014

651

526

591

606

21%

14%

18%

4%

9-Mar-12

22-Aug-10

-1.5

79%

16-Oct-09

15%

36%

Wigan 015A

149

83

108

123

61%

41%

59%

10%

9-Apr-09

22-Apr-10

1.0

69%

9-Apr-09

50%

52%

Wigan 015B

221

153

186

184

37%

36%

30%

7%

28-Feb-10

8-Feb-11

0.9

118%

27-Feb-10

31%

43%

Wigan 015C

192

142

166

160

30%

22%

22%

8%

12-Jan-10

30-Jun-11

1.5

97%

12-Jun-10

14%

18%

Wigan 015D

345

197

256

293

58%

16%

47%

6%

20-Mar-12

16-Jan-10

-2.2

34%

3-Jun-09

26%

41%

Wigan 015E

190

127

156

171

40%

10%

28%

8%

3-Apr-09

9-Mar-10

0.9

35%

3-Apr-09

17%

21%

Wigan 015

986

785

872

932

23%

6%

15%

3%

10-May-09

31-Dec-09

0.6

39%

11-May-09

10%

29%

Wigan 016A

161

111

141

151

35%

14%

27%

8%

29-Apr-09

19-Oct-11

2.5

53%

13-Feb-10

13%

15%

Wigan 016B

160

90

123

110

57%

31%

45%

9%

10-Feb-11

11-Feb-12

1.0

69%

29-Sep-09

6%

7%

Wigan 016C

137

96

113

118

36%

16%

27%

9%

25-Jan-11

20-Oct-09

-1.3

60%

2-Apr-09

10%

11%

Wigan 016D

41

21

32

35

63%

63%

54%

18%

8-Mar-12

29-Apr-10

-1.9

118%

29-Apr-09

30%

17%

Wigan 016E

200

137

174

173

36%

20%

31%

8%

4-Apr-09

23-Jan-12

2.8

66%

24-May-10

19%

25%

Wigan016

623

502

582

586

21%

10%

19%

4%

31-Mar-09

3-Feb-12

2.8

53%

12-Jun-10

7%

17%

Wigan 017A

58

35

45

48

51%

40%

51%

15%

18-Jan-10

12-Jan-11

1.0

78%

13-Jan-10

44%

30%

Wigan 017B

51

11

29

32

136%

95%

120%

18%

12-Oct-09

16-Nov-10

1.1

79%

12-Nov-09

102%

55%

Wigan 017C

30

15

22

23

69%

50%

69%

21%

23-Sep-09

23-Sep-10

1.0

73%

23-Sep-09

59%

28%

Wigan 017E

55

26

39

45

74%

36%

69%

16%

17-Dec-10

16-Dec-09

-1.0

52%

1-Jul-09

31%

19%

Wigan 017

170

105

136

148

48%

22%

48%

9%

13-Nov-09

16-Nov-10

1.0

46%

16-Nov-09

35%

41%

Wigan 018A

123

65

86

81

68%

57%

65%

11%

20-Jun-10

14-Jul-11

1.1

88%

28-May-10

47%

43%

Wigan 018B

141

93

119

125

40%

27%

40%

9%

12-May-10

19-Jul-11

1.2

67%

12-May-10

29%

32%

Wigan 018C

126

98

108

106

26%

25%

21%

10%

20-Jul-10

11-Jul-11

1.0

117%

27-May-10

18%

19%

Wigan 018D

78

39

62

56

63%

55%

55%

13%

25-Apr-10

15-Jan-12

1.7

100%

25-Apr-10

35%

27%

Wigan 018E

114

84

97

96

31%

29%

23%

10%

19-Oct-11

19-Feb-10

-1.7

127%

7-Apr-09

16%

16%

Wigan 018F

90

49

67

74

61%

42%

58%

12%

9-Jul-09

29-Aug-10

1.1

72%

13-Jul-09

48%

40%

Wigan 018G

77

47

60

62

50%

40%

50%

13%

21-Apr-10

21-Apr-09

-1.0

80%

21-Apr-10

37%

29%

Wigan 018

669

531

598

599

23%

20%

18%

4%

12-Dec-09

15-Jul-11

1.6

112%

12-Dec-09

17%

41%

Wigan 019A

113

69

96

91

46%

45%

36%

10%

10-Nov-10

9-Jul-09

-1.3

126%

15-Apr-09

4%

4%

Wigan 019B

78

48

66

69

45%

45%

36%

12%

26-Nov-11

24-Aug-10

-1.3

125%

24-Aug-09

26%

21%

Wigan 019C

136

97

115

119

34%

21%

32%

9%

23-Jan-10

23-Jan-11

1.0

65%

23-Jan-10

27%

28%

Wigan 019D

90

56

73

69

46%

41%

26%

12%

24-Aug-11

24-Aug-10

-1.0

158%

24-Aug-09

24%

20%

Wigan 019E

100

52

76

84

63%

37%

53%

11%

4-Dec-09

26-Oct-10

0.9

70%

4-Dec-09

43%

38%

Wigan 019

454

392

426

432

15%

13%

14%

5%

18-Sep-11

11-Aug-10

-1.1

92%

24-Aug-09

11%

24%

Wigan 020A

103

75

92

93

30%

30%

21%

10%

1-Apr-09

22-Mar-11

2.0

147%

1-Apr-09

20%

19%

Wigan 020B

75

49

59

64

44%

12%

32%

13%

7-Nov-11

11-Jun-09

-2.4

37%

26-Sep-09

11%

8%

Wigan 020C

137

76

103

111

59%

48%

35%

10%

16-Sep-09

27-Apr-11

1.6

139%

15-Sep-09

40%

40%

Wigan 020D

96

61

77

77

46%

33%

33%

11%

22-Oct-11

10-Mar-10

-1.6

100%

25-Apr-09

10%

9%

Wigan 020E

92

45

66

58

71%

49%

32%

12%

13-Jun-11

8-Apr-09

-2.2

152%

13-Jul-09

21%

17%

Wigan 020

443

369

397

404

19%

16%

13%

5%

6-Mar-12

15-Sep-10

-1.5

127%

15-Sep-09

12%

24%

Wigan 021A

83

46

65

67

57%

43%

52%

12%

20-Mar-12

19-Mar-11

-1.0

82%

20-Mar-10

45%

36%

Wigan 021B

98

51

75

79

63%

51%

47%

12%

1-Feb-12

3-Aug-10

-1.5

109%

6-Aug-09

25%

21%

Wigan 021C

65

30

50

45

71%

58%

34%

14%

24-Sep-09

21-Sep-11

2.0

171%

4-Mar-10

37%

26%

Wigan 021D

53

26

40

42

67%

40%

67%

16%

8-Jul-10

16-Jul-11

1.0

59%

25-May-10

42%

27%

Wigan 021E

79

53

65

66

40%

35%

38%

12%

7-Feb-11

3-Feb-12

1.0

92%

26-May-09

16%

13%

Wigan 021F

69

31

54

57

71%

30%

56%

14%

24-Feb-10

30-Nov-11

1.8

53%

24-Feb-10

32%

23%

Wigan 021G

100

69

81

85

38%

27%

32%

11%

22-Oct-09

17-Oct-10

1.0

85%

22-Oct-09

30%

27%

Wigan 021

484

400

430

441

20%

14%

17%

5%

5-Sep-09

10-Sep-10

1.0

84%

5-Sep-09

15%

32%

Wigan 022C

40

14

29

28

89%

89%

65%

19%

27-Feb-11

11-Feb-10

-1.0

137%

28-Apr-09

21%

11%

Wigan 022D

36

25

31

31

36%

23%

29%

18%

14-Jun-11

28-Jun-10

-1.0

78%

31-Mar-09

23%

13%

Wigan 022

74

42

60

59

53%

53%

43%

13%

27-Feb-11

26-Feb-10

-1.0

123%

31-Mar-09

19%

15%

Wigan 023A

47

18

31

37

93%

26%

61%

18%

31-Mar-12

9-Jul-11

-0.7

42%

11-Jun-10

24%

13%

Wigan 023B

53

21

37

36

87%

84%

73%

16%

17-Sep-09

29-Nov-11

2.2

115%

1-Sep-09

53%

32%

Wigan 023C

48

19

32

30

91%

75%

63%

18%

1-Oct-11

15-May-10

-1.4

120%

24-Apr-09

58%

33%

Wigan 023D

45

18

29

25

95%

95%

32%

19%

17-Aug-11

15-Jul-10

-1.1

300%

21-Apr-09

16%

8%

Wigan 023

150

110

129

128

31%

26%

25%

9%

8-Jan-11

29-Nov-11

0.9

106%

26-May-09

21%

23%

Wigan 024A

136

97

115

119

34%

22%

26%

9%

7-Jun-11

7-Jun-10

-1.0

83%

7-Jun-09

18%

20%

Wigan 024B

184

118

150

167

44%

21%

38%

8%

22-Aug-11

26-Sep-10

-0.9

56%

30-Sep-09

21%

26%

Wigan 024C

143

111

128

126

25%

20%

20%

9%

13-Oct-09

15-Oct-10

1.0

100%

15-Oct-09

20%

23%

Wigan 024D

100

80

91

91

22%

22%

18%

11%

30-May-10

16-May-11

1.0

125%

5-May-10

19%

18%

Wigan 024E

72

43

59

61

49%

37%

44%

13%

8-Jul-11

16-Sep-10

-0.8

85%

29-Sep-09

38%

29%

Wigan 024

596

493

542

564

19%

9%

19%

4%

16-Sep-11

30-Sep-10

-1.0

49%

3-Sep-09

14%

32%

Wigan 025A

39

14

24

29

105%

51%

80%

21%

21-Mar-12

3-Jan-10

-2.2

63%

31-Mar-09

40%

20%

Wigan 025B

29

13

21

23

77%

39%

53%

22%

28-Apr-10

28-Jun-11

1.2

73%

28-Apr-10

41%

19%

Wigan 025C

39

17

28

29

79%

40%

69%

19%

12-Dec-10

10-Nov-09

-1.1

58%

13-Jun-10

36%

19%

Wigan 025

101

46

72

81

76%

24%

54%

12%

27-Mar-12

3-Jan-10

-2.2

44%

2-May-10

19%

16%

Wigan 026A

96

55

76

76

54%

49%

45%

12%

13-Nov-11

10-Jul-10

-1.3

109%

12-Jul-09

40%

35%

Wigan 026B

91

55

74

70

48%

34%

31%

12%

6-Jul-11

17-Feb-10

-1.4

109%

11-May-09

28%

24%

Wigan 026C

109

66

83

93

52%

42%

46%

11%

8-Apr-09

17-Jul-10

1.3

92%

7-Sep-09

40%

36%

Wigan 026D

103

73

88

89

34%

34%

23%

11%

21-Dec-11

9-Nov-09

-2.1

150%

7-Apr-10

11%

11%

Wigan 026E

140

67

104

117

70%

49%

45%

10%

31-Mar-09

14-Apr-10

1.0

109%

10-Apr-09

45%

46%

Wigan 026

488

375

424

445

27%

24%

26%

5%

12-Apr-09

12-Jun-10

1.2

90%

15-Apr-09

23%

48%

Wigan 027A

165

85

127

143

63%

13%

41%

9%

30-Mar-12

7-Nov-11

-0.4

33%

7-Apr-10

23%

26%

Wigan 027B

109

70

92

84

43%

39%

22%

10%

8-Apr-10

11-Dec-10

0.7

180%

11-Dec-09

27%

26%

Wigan 027C

137

89

112

122

43%

25%

30%

9%

3-Aug-11

30-Jul-10

-1.0

82%

6-Jan-10

16%

17%

Wigan 027D

170

119

148

150

34%

22%

30%

8%

20-Sep-10

24-Nov-11

1.2

75%

7-May-10

13%

16%

Wigan 027E

64

31

48

51

69%

57%

63%

14%

20-Jan-12

20-Jan-11

-1.0

90%

18-Aug-09

48%

33%

Wigan 027

582

464

527

550

22%

11%

21%

4%

4-Apr-10

31-Mar-11

1.0

50%

5-Apr-10

16%

36%

Wigan 028A

34

19

26

24

58%

58%

43%

20%

26-Feb-11

4-Nov-11

0.7

136%

1-Sep-09

19%

10%

Wigan 029D

30

13

21

17

81%

53%

53%

22%

24-Mar-11

5-Feb-12

0.9

100%

4-Jun-10

12%

5%

Wigan 030A

88

59

73

70

40%

26%

27%

12%

23-Oct-11

9-Aug-11

-0.2

95%

30-May-10

12%

10%

Wigan 030B

122

74

99

108

48%

36%

44%

10%

23-Nov-11

26-Nov-10

-1.0

82%

11-Sep-09

35%

35%

Wigan 030C

89

47

71

79

59%

49%

53%

12%

28-Jul-11

16-Jun-10

-1.1

92%

20-Jun-09

32%

27%

Wigan 030D

85

47

64

59

60%

47%

38%

13%

11-Sep-10

4-Oct-11

1.1

125%

7-Apr-09

20%

16%

Wigan 030

335

277

307

315

19%

17%

14%

6%

19-Oct-11

4-Jul-10

-1.3

118%

6-May-09

11%

19%

Wigan 031A

126

63

86

83

73%

73%

56%

11%

6-Mar-10

5-Jan-11

0.8

131%

6-Mar-10

63%

59%

Wigan 031B

89

49

70

75

57%

19%

36%

12%

24-Jan-11

9-Jul-09

-1.5

52%

1-Jun-10

13%

11%

Wigan 031C

82

50

67

74

48%

25%

42%

12%

9-Oct-11

29-Sep-10

-1.0

61%

23-Aug-09

25%

21%

Wigan 031D

57

27

41

33

74%

49%

25%

16%

8-May-11

26-Mar-12

0.9

200%

13-Apr-09

15%

9%

Wigan 031E

385

259

333

350

38%

32%

36%

5%

4-Feb-12

6-Jan-11

-1.1

88%

15-Jan-10

27%

50%

Wigan 032A

108

73

88

86

40%

27%

27%

11%

12-Aug-11

19-Dec-09

-1.6

100%

23-Jul-09

11%

11%

Wigan 032B

85

59

70

72

37%

31%

37%

12%

30-Nov-09

11-Oct-10

0.9

85%

12-Oct-09

33%

27%

Wigan 032C

112

68

92

85

48%

28%

22%

10%

13-May-09

8-Mar-12

2.8

130%

10-May-09

10%

10%

Wigan 032D

204

131

167

178

44%

28%

37%

8%

20-Jun-09

13-Oct-10

1.3

77%

16-Oct-09

31%

41%

Wigan 032E

103

67

87

88

41%

29%

28%

11%

4-Apr-09

11-Jul-11

2.3

104%

31-May-10

22%

21%

Wigan 033A

98

60

76

82

50%

26%

30%

11%

14-Aug-11

22-Apr-09

-2.3

87%

3-Sep-09

10%

9%

Wigan 033B

119

79

99

106

40%

18%

26%

10%

2-Aug-11

14-Jan-10

-1.5

69%

27-May-09

19%

19%

Wigan 033C

79

35

62

56

71%

69%

34%

13%

17-Nov-09

11-Jun-11

1.6

205%

10-Jan-10

45%

35%

Wigan 033D

113

61

92

88

57%

40%

36%

10%

25-Jun-09

30-Sep-10

1.3

112%

13-Sep-09

38%

36%

Wigan 033E

241

150

190

204

48%

32%

28%

7%

21-Dec-11

13-Jul-09

-2.4

113%

13-Jun-10

12%

16%

Wigan 034A

98

53

74

83

61%

22%

41%

12%

15-Dec-10

15-Dec-09

-1.0

53%

3-Apr-09

24%

21%

Wigan 034B

68

42

54

54

48%

46%

39%

14%

17-Jun-10

17-Jun-11

1.0

119%

12-Jun-10

37%

27%

Wigan 034C

64

37

48

47

57%

57%

25%

15%

21-Oct-11

17-Aug-09

-2.2

225%

23-May-10

17%

12%

Wigan 034D

98

62

80

81

45%

27%

40%

11%

24-Sep-09

10-Jun-11

1.7

69%

1-Jun-10

31%

27%

Wigan 034E

95

64

75

75

41%

31%

29%

12%

2-Mar-12

19-Oct-11

-0.4

105%

25-May-09

11%

10%

Wigan 035A

245

159

205

189

42%

38%

32%

7%

11-Jun-10

27-Mar-12

1.8

118%

20-May-10

26%

37%

Wigan 035B

96

47

69

68

71%

71%

38%

12%

28-Sep-11

7-Nov-10

-0.9

188%

18-Nov-09

25%

21%

Wigan 035C

87

55

74

69

43%

41%

20%

12%

20-Feb-10

2-Apr-09

-0.9

200%

13-Feb-10

24%

21%

Wigan 035D

43

27

35

34

46%

35%

40%

17%

1-Nov-11

30-Oct-09

-2.0

86%

28-May-10

13%

8%

Wigan 035E

107

63

82

84

54%

46%

28%

11%

14-Sep-09

24-Mar-12

2.5

165%

14-Sep-09

37%

33%

Wigan 036A

175

114

142

131

43%

27%

20%

8%

7-Nov-10

19-Oct-09

-1.1

136%

31-Mar-09

2%

2%

Wigan 036B

149

100

127

131

39%

25%

31%

9%

26-Oct-09

18-May-11

1.6

82%

26-Oct-09

19%

22%

Wigan 036C

175

128

152

146

31%

22%

25%

8%

20-Mar-10

14-May-09

-0.8

89%

18-Mar-10

12%

15%

Wigan 036D

64

31

44

38

75%

64%

21%

15%

12-Sep-11

6-May-10

-1.4

311%

28-Aug-09

16%

11%

Wigan 036E

97

51

71

79

65%

17%

37%

12%

31-Mar-12

24-Dec-09

-2.3

46%

24-Apr-10

20%

17%

Wigan 036

583

502

535

526

15%

11%

11%

4%

15-Aug-11

18-Feb-12

0.5

100%

28-Apr-09

2%

4%

Wigan 037A

92

53

73

76

53%

52%

33%

12%

5-Jun-09

8-Aug-10

1.2

158%

28-May-09

40%

34%

Wigan 037B

106

63

85

91

51%

38%

49%

11%

3-Jan-12

29-Nov-10

-1.1

76%

3-Dec-09

38%

35%

Wigan 037C

79

38

52

59

79%

15%

70%

14%

9-Jan-11

29-Aug-09

-1.4

22%

n/a

0%

0%

Wigan 037D

85

44

61

61

67%

62%

62%

13%

29-Dec-09

12-Apr-11

1.3

100%

29-Dec-09

57%

45%

Wigan 037E

59

31

47

43

59%

38%

23%

15%

15-Apr-09

18-Feb-12

2.8

164%

15-Apr-09

21%

15%

Wigan 037

365

284

319

329

25%

16%

24%

6%

4-Jun-09

28-Dec-10

1.6

67%

30-Dec-09

20%

35%

Wigan 038A

87

60

73

70

37%

28%

29%

12%

10-Jul-11

6-Mar-12

0.7

95%

26-Aug-09

21%

18%

Wigan 038B

80

48

66

66

49%

36%

43%

12%

1-Jul-11

31-Jan-10

-1.4

86%

31-Mar-09

7%

6%

Wigan 038C

115

74

93

88

44%

42%

35%

10%

13-Feb-10

18-Feb-11

1.0

122%

18-Feb-10

37%

36%

Wigan 038D

144

107

130

132

28%

18%

22%

9%

21-Oct-09

13-Mar-12

2.4

82%

3-Nov-09

17%

19%

Wigan 038E

114

69

93

88

48%

40%

39%

10%

5-Feb-10

5-Feb-11

1.0

103%

5-Feb-10

39%

38%

Wigan 038

494

407

454

444

19%

16%

11%

5%

1-Sep-09

8-Apr-11

1.6

143%

11-Apr-10

12%

27%

Wigan 039A

78

42

64

64

56%

44%

37%

12%

8-Apr-09

1-Oct-10

1.5

117%

1-Oct-09

37%

29%

Wigan 039B

100

68

81

78

39%

36%

36%

11%

9-Jul-10

6-Apr-09

-1.3

100%

10-Jun-10

25%

22%

Wigan 039C

55

27

42

40

67%

52%

45%

15%

4-Oct-09

25-Feb-12

2.4

116%

14-Oct-09

44%

29%

Wigan 039D

101

51

74

74

68%

64%

45%

12%

24-Mar-12

4-May-11

-0.9

142%

5-May-10

32%

27%

Wigan 039

290

220

261

256

27%

17%

18%

6%

7-Oct-09

20-Mar-11

1.4

92%

20-Mar-10

16%

27%

Wigan 039E

79

44

58

64

60%

10%

38%

13%

29-Mar-12

15-Jan-10

-2.2

27%

5-Aug-09

12%

9%

Wigan 040A

60

26

43

52

79%

35%

63%

15%

2-Apr-09

2-Jul-10

1.2

56%

3-Jul-09

42%

28%

Wigan 040B

73

41

58

65

55%

36%

41%

13%

28-May-09

3-Sep-10

1.3

88%

28-May-09

34%

26%

Wigan 040C

83

46

65

65

57%

56%

54%

12%

14-Dec-11

27-Dec-10

-1.0

103%

27-Dec-09

46%

37%

Wigan 040D

189

101

140

127

63%

48%

26%

8%

27-Dec-11

7-Jan-11

-1.0

181%

16-Dec-09

28%

33%

Wigan 040E

71

38

52

48

64%

50%

37%

14%

30-Aug-11

6-Dec-09

-1.7

137%

23-Feb-10

6%

4%

Wigan 040

415

299

358

357

32%

30%

23%

5%

24-Nov-11

16-Dec-10

-0.9

130%

22-Jan-10

19%

37%

Table S3: Demographic and social group characteristics for Wigan LSOA

LSOA Code

LSOA Name

LSOA type and social classification

Population Details

Admissions

Step-change STDEV

Urban Type

OAC Code

OAC Type

IMD

Population Density

Aged 70+ (%)

Max

Min

Step-up

Step-down

Max

E01006231

Wigan 004A

Rural town and fringe

1.2a

Rural Economiesa

19

2

13%

101

58

5.1

1.1

5.1

E01006232

Wigan 004B

Urban major conurbation

1.2a

Rural Economiesa

8

2

11%

101

60

3.1

3.6

3.6

E01006277

Wigan 016D

Urban major conurbation

3.1a

Urban Commutera

6

26

3%

41

21

5.3

2.4

5.3

E01006395

Wigan 021C

Urban major conurbation

3.1a

Urban Commutera

5

10

3%

65

30

6.8

1.9

6.8

E01006400

Wigan 021D

Urban major conurbation

3.1a

Urban Commutera

9

24

3%

53

26

2.7

3.2

3.2

E01006224

Wigan 035D

Urban major conurbation

3.1a

Urban Commutera

8

40

2%

43

27

2.3

2.0

2.3

E01006343

Wigan 039C

Urban major conurbation

3.1a

Urban Commutera

7

50

4%

55

27

4.5

2.5

4.5

E01006321

Wigan 003G

Urban city and town

3.1b

Urban Commuterb

6

40

8%

80

26

5.2

4.7

5.2

E01006315

Wigan 001A

Urban major conurbation

3.1b

Urban Commuterb

8

5

13%

109

54

6.4

3.8

6.4

E01006233

Wigan 002C

Urban major conurbation

3.1b

Urban Commuterb

7

17

13%

120

74

3.3

2.4

3.3

E01006318

Wigan 003E

Urban major conurbation

3.1b

Urban Commuterb

14

23

14%

98

64

2.5

2.3

2.5

E01006320

Wigan 003F

Urban major conurbation

3.1b

Urban Commuterb

7

9

10%

68

33

3.7

1.4

3.7

E01006372

Wigan 006B

Urban major conurbation

3.1b

Urban Commuterb

5

21

17%

157

115

3.9

2.3

3.9

E01006363

Wigan 018B

Urban major conurbation

3.1b

Urban Commuterb

12

39

26%

141

93

3.3

3.7

3.7

E01006393

Wigan 021A

Urban major conurbation

3.1b

Urban Commuterb

8

57

8%

83

46

4.9

3.4

4.9

E01006394

Wigan 021B

Urban major conurbation

3.1b

Urban Commuterb

9

26

14%

98

51

5.7

3.5

5.7

E01006402

Wigan 021F

Urban major conurbation

3.1b

Urban Commuterb

8

60

8%

69

31

2.2

3.6

3.6

E01006403

Wigan 021G

Urban major conurbation

3.1b

Urban Commuterb

12

37

10%

100

69

2.6

2.4

2.6

E01006330

Wigan 031C

Urban major conurbation

3.1b

Urban Commuterb

10

42

11%

82

50

2.8

2.9

2.9

E01006331

Wigan 031D

Urban major conurbation

3.1b

Urban Commuterb

14

27

8%

57

27

4.1

1.7

4.1

E01006263

Wigan 032B

Urban major conurbation

3.1b

Urban Commuterb

9

30

16%

85

59

3.1

2.6

3.1

E01006222

Wigan 035C

Urban major conurbation

3.1b

Urban Commuterb

12

24

11%

87

55

4.7

1.8

4.7

E01006264

Wigan 036D

Urban major conurbation

3.1b

Urban Commuterb

7

41

8%

64

31

5.1

1.4

5.1

E01006300

Wigan 037D

Urban major conurbation

3.1b

Urban Commuterb

8

39

21%

85

44

6.3

3.5

6.3

E01006301

Wigan 037E

Urban major conurbation

3.1b

Urban Commuterb

10

10

11%

59

31

4.0

1.4

4.0

E01006339

Wigan 039A

Urban major conurbation

3.1b

Urban Commuterb

13

32

12%

78

42

5.2

2.5

5.2

E01006348

Wigan 039E

Urban major conurbation

3.1b

Urban Commuterb

11

3

16%

79

44

1.0

2.3

2.3

E01006347

Wigan 040E

Urban major conurbation

3.1b

Urban Commuterb

7

42

16%

71

38

4.2

2.4

4.2

E01006230

Wigan 002B

Urban major conurbation

3.2b

Affluent Urban Commuterb

8

15

12%

76

48

3.2

2.9

3.2

E01006236

Wigan 007A

Rural village and dispersed

4.1a

Well off Mature Householdsa

11

3

13%

89

52

4.5

2.5

4.5

E01006312

Wigan 003B

Urban city and town

4.1a

Well off Mature Householdsa

7

30

14%

98

56

3.6

2.7

3.6

E01006316

Wigan 001B

Urban major conurbation

4.1a

Well off Mature Householdsa

10

11

10%

74

34

6.2

3.4

6.2

E01006229

Wigan 002A

Urban major conurbation

4.1a

Well off Mature Householdsa

11

6

18%

152

98

1.5

2.7

2.7

E01006314

Wigan 003D

Urban major conurbation

4.1a

Well off Mature Householdsa

8

7

17%

151

66

5.5

5.7

5.7

E01006255

Wigan 005C

Urban major conurbation

4.1a

Well off Mature Householdsa

13

58

14%

92

60

3.4

2.9

3.4

E01006373

Wigan 006C

Urban major conurbation

4.1a

Well off Mature Householdsa

8

54

13%

98

42

3.8

3.3

3.8

E01006258

Wigan 008B

Urban major conurbation

4.1a

Well off Mature Householdsa

17

53

14%

136

95

3.5

2.9

3.5

E01006271

Wigan 013B

Urban major conurbation

4.1a

Well off Mature Householdsa

17

17

12%

159

104

5.3

2.7

5.3

E01006362

Wigan 018A

Urban major conurbation

4.1a

Well off Mature Householdsa

9

10

15%

123

65

6.3

4.2

6.3

E01006367

Wigan 018F

Urban major conurbation

4.1a

Well off Mature Householdsa

10

27

16%

90

49

3.8

3.6

3.8

E01006281

Wigan 019D

Urban major conurbation

4.1a

Well off Mature Householdsa

10

27

9%

90

56

4.3

2.1

4.3

E01006243

Wigan 023B

Urban major conurbation

4.1a

Well off Mature Householdsa

16

13

10%

53

21

9.0

3.2

9.0

E01006252

Wigan 034C

Urban major conurbation

4.1a

Well off Mature Householdsa

13

57

13%

64

37

5.0

1.7

5.0

E01006225

Wigan 036B

Urban major conurbation

4.1a

Well off Mature Householdsa

14

27

19%

149

100

3.2

3.2

3.2

E01006299

Wigan 037C

Urban major conurbation

4.1a

Well off Mature Householdsa

14

10

9%

79

38

1.5

3.4

3.4

E01006345

Wigan 039D

Urban major conurbation

4.1a

Well off Mature Householdsa

10

51

15%

101

51

7.5

3.3

7.5

E01006302

Wigan 040A

Urban major conurbation

4.1a

Well off Mature Householdsa

12

15

6%

60

26

2.2

3.0

3.0

E01006374

Wigan 006D

Urban major conurbation

4.1b

Well off Mature Householdsb

15

40

16%

102

47

7.4

3.8

7.4

E01006355

Wigan 014C

Urban major conurbation

4.1b

Well off Mature Householdsb

21

68

11%

121

65

7.7

3.9

7.7

E01006266

Wigan 032C

Urban major conurbation

4.1b

Well off Mature Householdsb

14

38

18%

112

68

3.0

1.8

3.0

E01006226

Wigan 035E

Urban major conurbation

4.1b

Well off Mature Householdsb

16

27

10%

107

63

5.0

2.4

5.0

E01006256

Wigan 005D

Urban major conurbation

4.2a

Young Urban Familiesa

23

36

10%

96

43

5.4

4.4

5.4

E01006396

Wigan 011B

Urban major conurbation

4.2a

Young Urban Familiesa

15

6

10%

141

83

6.4

2.7

6.4

E01006276

Wigan 013E

Urban major conurbation

4.2a

Young Urban Familiesa

16

23

6%

81

52

2.2

2.5

2.5

E01006286

Wigan 016E

Urban major conurbation

4.2a

Young Urban Familiesa

23

43

16%

200

137

3.0

3.7

3.7

E01006279

Wigan 019B

Urban major conurbation

4.2a

Young Urban Familiesa

12

41

7%

78

48

5.1

2.6

5.1

E01006285

Wigan 019E

Urban major conurbation

4.2a

Young Urban Familiesa

14

23

9%

100

52

3.4

3.5

3.5

E01006406

Wigan 020A

Urban major conurbation

4.2a

Young Urban Familiesa

29

37

11%

103

75

3.6

1.9

3.6

E01006407

Wigan 020B

Urban major conurbation

4.2a

Young Urban Familiesa

12

15

5%

75

49

1.0

2.0

2.0

E01006409

Wigan 020D

Urban major conurbation

4.2a

Young Urban Familiesa

14

69

16%

96

61

3.4

2.5

3.4

E01006410

Wigan 020E

Urban major conurbation

4.2a

Young Urban Familiesa

12

24

8%

92

45

5.3

2.4

5.3

E01006401

Wigan 021E

Urban major conurbation

4.2a

Young Urban Familiesa

11

6

10%

79

53

3.3

2.6

3.3

E01006292

Wigan 022C

Urban major conurbation

4.2a

Young Urban Familiesa

17

33

13%

40

14

10.0

3.1

10.0

E01006219

Wigan 024E

Urban major conurbation

4.2a

Young Urban Familiesa

22

57

6%

72

43

3.9

2.9

3.9

E01006212

Wigan 026A

Urban major conurbation

4.2a

Young Urban Familiesa

19

14

10%

96

55

5.5

3.3

5.5

E01006216

Wigan 026C

Urban major conurbation

4.2a

Young Urban Familiesa

21

18

5%

109

66

4.5

3.2

4.5

E01006282

Wigan 027A

Urban major conurbation

4.2a

Young Urban Familiesa

35

21

10%

165

85

2.0

4.3

4.3

E01006268

Wigan 032E

Urban major conurbation

4.2a

Young Urban Familiesa

21

28

9%

103

67

3.5

2.2

3.5

E01006325

Wigan 033C

Urban major conurbation

4.2a

Young Urban Familiesa

25

38

7%

79

35

9.5

2.1

9.5

E01006247

Wigan 034B

Urban major conurbation

4.2a

Young Urban Familiesa

15

29

14%

68

42

4.3

2.4

4.3

E01006221

Wigan 035B

Urban major conurbation

4.2a

Young Urban Familiesa

16

38

12%

96

47

8.7

2.8

8.7

E01006227

Wigan 038A

Urban major conurbation

4.2a

Young Urban Familiesa

13

45

9%

87

60

2.6

2.2

2.6

E01006303

Wigan 040B

Urban major conurbation

4.2a

Young Urban Familiesa

12

6

11%

73

41

3.5

2.7

3.5

E01006319

Wigan 001D

Urban major conurbation

4.2b

Young Urban Familiesb

7

36

6%

57

29

4.0

2.4

4.0

E01006237

Wigan 002D

Urban major conurbation

4.2b

Young Urban Familiesb

4

11

8%

76

40

6.1

1.5

6.1

E01006259

Wigan 003A

Urban major conurbation

4.2b

Young Urban Familiesb

17

14

12%

91

60

2.2

2.3

2.3

E01006389

Wigan 007C

Urban major conurbation

4.2b

Young Urban Familiesb

16

53

4%

59

28

1.2

2.3

2.3

E01006365

Wigan 018D

Urban major conurbation

4.2b

Young Urban Familiesb

6

29

6%

78

39

6.8

3.4

6.8

E01006234

Wigan 004C

Rural town and fringe

4.3a

Mature Urban Householdsa

15

20

15%

99

59

5.3

2.5

5.3

E01006317

Wigan 001C

Urban major conurbation

4.3a

Mature Urban Householdsa

19

26

13%

118

86

3.1

2.3

3.1

E01006390

Wigan 006E

Urban major conurbation

4.3a

Mature Urban Householdsa

24

38

18%

133

85

4.2

3.7

4.2

E01006391

Wigan 007D

Urban major conurbation

4.3a

Mature Urban Householdsa

19

28

13%

126

72

4.0

3.7

4.0

E01006399

Wigan 011E

Urban major conurbation

4.3a

Mature Urban Householdsa

29

29

13%

135

86

1.4

3.4

3.4

E01006353

Wigan 014A

Urban major conurbation

4.3a

Mature Urban Householdsa

31

49

13%

125

84

3.8

3.4

3.8

E01006366

Wigan 018E

Urban major conurbation

4.3a

Mature Urban Householdsa

18

13

17%

114

84

3.2

2.0

3.2

E01006278

Wigan 019A

Urban major conurbation

4.3a

Mature Urban Householdsa

24

30

14%

113

69

6.1

3.2

6.1

E01006280

Wigan 019C

Urban major conurbation

4.3a

Mature Urban Householdsa

27

38

16%

136

97

2.3

2.9

2.9

E01006337

Wigan 027E

Urban major conurbation

4.3a

Mature Urban Householdsa

20

35

10%

64

31

6.0

3.4

6.0

E01006261

Wigan 036C

Urban major conurbation

4.3a

Mature Urban Householdsa

25

56

17%

175

128

3.2

2.8

3.2

E01006340

Wigan 039B

Urban major conurbation

4.3a

Mature Urban Householdsa

29

4

10%

100

68

3.8

2.6

3.8

E01006304

Wigan 040C

Urban major conurbation

4.3a

Mature Urban Householdsa

19

8

14%

83

46

6.3

3.5

6.3

E01006341

Wigan 040D

Urban major conurbation

4.3a

Mature Urban Householdsa

28

30

12%

189

101

6.6

2.8

6.6

E01006368

Wigan 018G

Urban city and town

4.3c

Mature Urban Householdsc

19

3

15%

77

47

3.9

3.0

3.9

E01006387

Wigan 009D

Urban major conurbation

4.3c

Mature Urban Householdsc

26

71

15%

204

63

10.7

1.9

10.7

E01006273

Wigan 013D

Urban major conurbation

4.3c

Mature Urban Householdsc

31

20

10%

122

68

6.1

4.1

6.1

E01006245

Wigan 023D

Urban major conurbation

4.3c

Mature Urban Householdsc

23

8

6%

45

18

8.0

1.8

8.0

E01006265

Wigan 036E

Urban major conurbation

4.3c

Mature Urban Householdsc

22

41

11%

97

51

1.9

2.7

2.7

E01006228

Wigan 038B

Urban major conurbation

4.3c

Mature Urban Householdsc

25

18

7%

80

48

3.7

3.0

3.7

E01006346

Wigan 038E

Urban major conurbation

4.3c

Mature Urban Householdsc

20

19

11%

114

69

4.6

3.0

4.6

E01006248

Wigan 031A

Rural town and fringe

6.1a

Struggling Urban Familiesa

67

14

11%

126

63

9.3

3.6

9.3

E01006306

Wigan 009A

Urban major conurbation

6.1a

Struggling Urban Familiesa

50

64

14%

195

132

2.9

3.6

3.6

E01006386

Wigan 009C

Urban major conurbation

6.1a

Struggling Urban Familiesa

66

61

18%

277

189

1.8

3.3

3.3

E01006411

Wigan 015E

Urban major conurbation

6.1a

Struggling Urban Familiesa

64

32

9%

190

127

1.1

2.9

2.9

E01006239

Wigan 017A

Urban major conurbation

6.1a

Struggling Urban Familiesa

60

40

11%

58

35

3.0

2.7

3.0

E01006289

Wigan 017E

Urban major conurbation

6.1a

Struggling Urban Familiesa

58

52

10%

55

26

3.4

3.2

3.4

E01006267

Wigan 032D

Urban major conurbation

6.1a

Struggling Urban Familiesa

46

60

16%

204

131

4.0

3.9

4.0

E01006298

Wigan 037B

Urban major conurbation

6.1a

Struggling Urban Familiesa

41

63

12%

106

63

4.6

3.7

4.6

E01006392

Wigan 009E

Urban major conurbation

6.1b

Struggling Urban Familiesb

58

54

7%

128

98

2.3

2.5

2.5

E01006351

Wigan 010B

Urban major conurbation

6.1b

Struggling Urban Familiesb

73

53

7%

191

130

4.5

3.8

4.5

E01006240

Wigan 017B

Urban major conurbation

6.1b

Struggling Urban Familiesb

64

54

6%

51

11

10.9

3.8

10.9

E01006336

Wigan 027D

Urban major conurbation

6.1b

Struggling Urban Familiesb

55

28

11%

170

119

2.9

3.3

3.3

E01006249

Wigan 031B

Rural town and fringe

6.2a

Blue Collar Urban Familiesa

45

13

7%

89

49

1.8

2.8

2.8

E01006357

Wigan 010C

Urban major conurbation

6.2a

Blue Collar Urban Familiesa

66

24

10%

248

175

2.1

3.5

3.5

E01006356

Wigan 011A

Urban major conurbation

6.2a

Blue Collar Urban Familiesa

42

56

8%

118

82

2.3

2.9

2.9

E01006311

Wigan 012E

Urban major conurbation

6.2a

Blue Collar Urban Familiesa

38

18

7%

110

76

2.5

2.2

2.5

E01006359

Wigan 014E

Urban major conurbation

6.2a

Blue Collar Urban Familiesa

34

42

8%

107

67

3.4

2.4

3.4

E01006262

Wigan 032A

Urban major conurbation

6.2a

Blue Collar Urban Familiesa

32

6

8%

108

73

3.1

2.3

3.1

E01006344

Wigan 038D

Urban major conurbation

6.2a

Blue Collar Urban Familiesa

40

57

14%

144

107

2.2

2.4

2.4

E01006235

Wigan 004D

Rural town and fringe

6.2b

Blue Collar Urban Familiesb

34

24

16%

127

90

3.1

3.0

3.1

E01006215

Wigan 024B

Rural town and fringe

6.2b

Blue Collar Urban Familiesb

53

4

14%

184

118

3.3

4.0

4.0

E01006238

Wigan 002E

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

31

59

15%

143

98

2.9

2.4

2.9

E01006313

Wigan 003C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

32

12

12%

96

61

2.4

3.2

3.2

E01006253

Wigan 005A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

37

46

16%

120

84

4.3

2.3

4.3

E01006254

Wigan 005B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

49

15

9%

149

98

5.8

2.5

5.8

E01006260

Wigan 005E

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

30

32

12%

130

101

2.0

2.3

2.3

E01006388

Wigan 007B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

24

34

12%

169

105

2.8

4.3

4.3

E01006307

Wigan 009B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

39

34

10%

144

108

1.5

2.7

2.7

E01006350

Wigan 010A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

66

22

7%

168

121

1.9

2.5

2.5

E01006360

Wigan 010D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

64

33

8%

223

114

9.8

5.4

9.8

E01006361

Wigan 010E

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

58

13

6%

161

106

1.5

3.2

3.2

E01006397

Wigan 011C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

37

79

16%

133

78

4.0

3.9

4.0

E01006398

Wigan 011D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

32

48

10%

78

58

1.4

1.6

1.6

E01006305

Wigan 012A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

55

47

8%

182

100

3.9

4.3

4.3

E01006308

Wigan 012B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

42

14

11%

176

134

1.8

2.0

2.0

E01006309

Wigan 012C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

41

25

8%

182

132

2.6

2.8

2.8

E01006310

Wigan 012D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

45

6

10%

198

96

0.6

4.4

4.4

E01006354

Wigan 014B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

36

69

17%

222

163

4.8

3.5

4.8

E01006358

Wigan 014D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

36

28

15%

139

103

2.9

2.1

2.9

E01006404

Wigan 015C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

37

28

12%

192

142

3.3

2.5

3.3

E01006405

Wigan 015D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

41

36

13%

345

197

2.7

5.6

5.6

E01006270

Wigan 016A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

45

55

14%

161

111

1.7

3.0

3.0

E01006274

Wigan 016B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

35

73

12%

160

90

3.4

3.8

3.8

E01006275

Wigan 016C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

49

54

12%

137

96

1.8

2.3

2.3

E01006241

Wigan 017C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

49

14

7%

30

15

2.8

2.3

2.8

E01006408

Wigan 020C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

34

44

10%

137

76

5.8

3.2

5.8

E01006213

Wigan 024A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

54

8

7%

136

97

2.8

2.5

2.8

E01006217

Wigan 024C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

33

25

7%

143

111

2.5

2.1

2.5

E01006218

Wigan 024D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

39

35

5%

100

80

2.4

1.5

2.4

E01006288

Wigan 025A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

49

12

8%

39

14

4.2

2.4

4.2

E01006322

Wigan 026D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

44

5

7%

103

73

3.8

1.9

3.8

E01006283

Wigan 027B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

43

20

8%

109

70

4.9

2.1

4.9

E01006284

Wigan 027C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

40

49

7%

137

89

3.3

2.9

3.3

E01006376

Wigan 028A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

35

25

10%

34

19

4.0

1.7

4.0

E01006380

Wigan 029D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

34

15

14%

30

13

2.6

1.7

2.6

E01006324

Wigan 033B

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

38

57

11%

119

79

2.1

2.2

2.2

E01006327

Wigan 033E

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

65

5

12%

241

150

5.5

3.2

5.5

E01006297

Wigan 034D

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

44

12

11%

98

62

2.7

2.9

2.9

E01006220

Wigan 035A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

33

5

14%

245

159

6.9

4.1

6.9

E01006296

Wigan 037A

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

49

28

8%

92

53

6.1

2.3

6.1

E01006342

Wigan 038C

Urban major conurbation

6.2b

Blue Collar Urban Familiesb

39

32

14%

115

74

5.0

2.7

5.0

E01006370

Wigan 006A

Urban major conurbation

7.2a

Resorts and Retirementa

23

29

10%

136

77

3.5

3.5

3.5

E01006375

Wigan 008E

Urban major conurbation

7.2a

Resorts and Retirementa

12

45

10%

92

52

5.6

2.8

5.6

E01006369

Wigan 008C

Urban major conurbation

7.3a

Urban Terracinga

44

22

10%

163

114

4.4

3.3

4.4

E01006328

Wigan 030A

Urban major conurbation

7.3a

Urban Terracinga

40

50

9%

88

59

2.4

2.2

2.4

E01006272

Wigan 013C

Urban major conurbation

7.3b

Urban Terracingb

29

9

13%

181

106

5.4

4.8

5.4

E01006349

Wigan 015A

Urban major conurbation

7.3b

Urban Terracingb

31

10

10%

149

83

4.4

4.5

4.5

E01006352

Wigan 015B

Urban major conurbation

7.3b

Urban Terracingb

42

26

12%

221

153

5.9

3.6

5.9

E01006242

Wigan 023A

Urban major conurbation

7.3b

Urban Terracingb

25

20

14%

47

18

2.2

2.9

2.9

E01006294

Wigan 025B

Urban major conurbation

7.3b

Urban Terracingb

24

52

6%

29

13

2.0

2.0

2.0

E01006295

Wigan 025C

Urban major conurbation

7.3b

Urban Terracingb

32

47

9%

39

17

2.9

2.6

2.9

E01006214

Wigan 026B

Urban major conurbation

7.3b

Urban Terracingb

37

8

8%

91

55

3.6

2.4

3.6

E01006333

Wigan 030B

Urban major conurbation

7.3b

Urban Terracingb

38

39

8%

122

74

4.8

3.7

4.8

E01006338

Wigan 030D

Urban major conurbation

7.3b

Urban Terracingb

29

71

10%

85

47

4.5

2.3

4.5

E01006323

Wigan 033A

Urban major conurbation

7.3b

Urban Terracingb

45

21

8%

98

60

2.9

2.3

2.9

E01006326

Wigan 033D

Urban major conurbation

7.3b

Urban Terracingb

35

87

9%

113

61

5.3

2.9

5.3

E01006335

Wigan 034E

Urban major conurbation

7.3b

Urban Terracingb

25

89

7%

95

64

3.1

2.2

3.1

E01006223

Wigan 036A

Urban major conurbation

7.3b

Urban Terracingb

22

43

12%

175

114

3.8

2.3

3.8

E01006257

Wigan 008A

Urban major conurbation

7.3c

Urban Terracingc

16

87

12%

90

57

1.2

1.7

1.7

E01006371

Wigan 008D

Urban major conurbation

7.3c

Urban Terracingc

16

58

10%

91

62

3.5

2.3

3.5

E01006334

Wigan 030C

Urban major conurbation

7.3c

Urban Terracingc

37

54

6%

89

47

6.3

3.7

6.3

E01006269

Wigan 013A

Urban major conurbation

7.4a

Small Town Communitiesa

29

24

12%

133

89

4.3

3.3

4.3

E01006364

Wigan 018C

Urban major conurbation

7.4a

Small Town Communitiesa

25

14

13%

126

98

2.8

1.9

2.8

E01006244

Wigan 023C

Urban major conurbation

7.4a

Small Town Communitiesa

28

16

18%

48

19

7.1

2.9

7.1

E01006329

Wigan 026E

Urban major conurbation

7.4a

Small Town Communitiesa

39

7

9%

140

67

5.9

3.4

5.9

E01006332

Wigan 031E

Urban major conurbation

7.4a

Small Town Communitiesa

22

36

15%

385

259

7.5

5.7

7.5

E01006293

Wigan 022D

Urban major conurbation

7.4b

Small Town Communitiesb

30

16

14%

36

25

1.6

1.5

1.6

E01006246

Wigan 034A

Urban major conurbation

7.4b

Small Town Communitiesb

31

20

13%

98

53

2.2

2.8

2.8

Timing of the maximum step-change

The initiation dates for both the maximum step-up and step-down (12 months after initiation), can be used to demonstrate if the step-like events are clustered in time. From Figure 1 there may be the possibility of several step-down events after the 2007/08 event, the 2010/11 event has full coverage, while the 2012/13 event will be revealed by step-up features. Figure 4 summarizes the timing for the events captured at MSOA/LSOA level. As can be seen only six step-down events (with a maximum magnitude) were captured in the period Mar-08 to Aug-08, i.e. the bulk of the spatial spread associated with the 2007/08 event occurred too early for capture in this study.

Figure 4. Month of initiation of the events as deduced from maximum step-up and maximum step-down for these events in LSOA and MSOA in Wigan. Initiation derived from the step-down was assumed to occur 365 days earlier

However the 2010/11 event is well represented and appears to occur between Oct-08 through to Oct-10 or Mar-11 with greatest initiation occurring Aug-09 to Oct-09. The leading edge of the 2012/13 event probably overlaps the tailing edge of the 2010/11 event during the period Sep-10 to Mar-11, while the bulk of initiation commences after Jun-11 with a peak around Mar-12. Once again the duration of the study prevents full characterization beyond Mar-12.

The two year period of small area spread for the 2009/10 event revealed in this study, explains why the peak in deaths for this event in Figure 1 is not as sharp as the peaks seen for the other events in Figure 1. This concurs with other studies which suggest that the spread of deaths across the UK and Europe can occur more rapidly in some events than others [15,17,41]. It is clear that the mechanisms of spread, and any environmental factors leading to faster or slower spread, need to be understood.

Table S1 (supplementary material) shows the corresponding points in the running 365 day total at which the maximum or minimum total occurs (100 largest LSOA or other areas). As can be seen, the maximum or minimum can occur at any point in the four year period. Contrary to expectation the minimum occurs more frequently toward the end of the period than the start, i.e. population demography cannot be the major driving force for change. The most prominent minimum also occurs after the 2010 event but before the 2012 event.

Effect of socio-demographic variables on the maximum step-change

It is possible that socio-demographic variables may affect the magnitude of the observed step-change and roles for deprivation - as Index of Multiple Deprivation (IMD), population density, social grouping and age (as proportion of persons aged 70+) were all investigated. Figure 3 illustrates the importance of adjusting any step-change for the effects of size, and this was achieved by converting the magnitude of the step-change into standard deviation (STDEV) equivalents, i.e. magnitude of the step change divided by the square root of the average number of admissions.

Neither the IMD (range 4 to 73 in Wigan), or population density (range 2 to 90 persons per hectare in Wigan) showed any correlation with the magnitude of the step-change (see Table S3 in the supplementary material for a list of IMD, population density and social classification relating to each LSOA). However, as illustrated in Figure 5, social grouping appeared to show an effect with social groups containing older persons showing the greatest average step-change (as STDEV equivalents). Roughly similar differences in magnitude were observed between social groups in North East Essex following the 2008/09 event [21].

Figure 5. Effect of social group classification on the average maximum step-change converted into standard deviation equivalents

A potential role for age was further investigated by investigating the role of proportion of persons aged 70+ on the average maximum step-change, and is presented in Figure 6 where a running average of 10 size-ranked LSOA is used to minimize the scatter. The line of best fit is a simple second order polynomial via the’ add trend line’ function in Excel. As can be seen there is a modest effect of proportion aged 70+ at less than 12% after which the effect reaches an asymptote. A theoretical population containing no people aged 70+ would have a 1.25 standard deviation equivalent lower step-change than populations containing >12% of persons aged 70+. Hence age appears to be the only factor having an effect on the magnitude of the step-change and this is consistent with that observed elsewhere [22-24]. Indeed it has been suggested that the actual value of the step-increase is single-year-of-age specific [22,42], and this has been interpreted to imply that different strains of the same agent lead to these infectious-like events.

Figure 6. Effect of proportion of persons aged 70+ on the average step-change (STDEV equivalents) as running average of 10 proportion aged 70+-ranked LSOA

The 2009/10 outbreak

In terms of the effect upon deaths across the UK, the 2010 event made only a small effect and would otherwise be assumed not to exist. It was only when this author was examining trends at Local Authority level that the possibility of an additional event began to emerge [18]. Given that the time span of this study allows complete characterization of the 2010 event, both the timing and magnitude of the step-increase was characterized in all MSOA/LSOA in Wigan. Since both step-up and step-down are available, a method was employed which looked for the point in time when the magnitude of the step-up and step-down reached a maximum. This method effectively determines the point at which the area under the inverted V arising from the running total method is maximized. The average value of the step-up and step-down associated with this point was calculated along with the associated date.

Given the dependence on size noted in Figure 2, all percentage step-changes were adjusted to the theoretical value at an average of 100 admissions per annum, as follows: Observed step-change (%) x square root of (average admissions/100). The resulting size-adjusted step-changes ranged from +0% (Wigan 037C) to +198% (Wigan 017B). The average and median increases were 50% and 43% respectively while the interquartile range was 27% to 67%. Some 11% of LSOA experience greater than a 68% increase (2 x median) in medical admissions. Asimilar magnitude of increase in deaths has been characterized in equivalent sized locations in Australia [41].

As can be seen in Figure 7 the cumulative distribution is skewed. This skewing is evident in that at the left-hand tail 10% of locations experience a size- adjusted increase of between 0% and 18% (range 18%), while in the right-hand tail10% of locations experience size-adjusted increases of between 86% and 198% (range 112%). In addition, the standard deviation is ± 29% which encompasses 9.1% of values in the left-hand tail, but only 0.4% of values in the right-hand tail. Hence this infectious-like event is clearly highly granular/heterogeneous with respect to its effect on increased medical admissions, and this behavior is consistent with the known behavior of infectious events [18].

Figure 7. Cumulative proportion of areas, and percentage magnitude of the 2009/10 (size-adjusted) step-increase

As can be seen in Figure 8 there are three clusters of higher frequency of initiation around April/May 2009 (18% of locations), September/October 2009 (17%) and April/May 2010 (17%), while the frequency of initiation for other two month pairs only ranges from 8% to 12%. At the moment, the significance of the repeat April/May pairs toward the start and end of the outbreak will require further studies to see if this represents a significant period for these outbreaks in general. The median value of the (size-adjusted) step-increase in admissions also appears to peak at around the chronological mid-point of the outbreak, i.e. October and December 2009. A simple second order polynomial, using the ‘add trend line’ function in Excel, has been added to Figure 8 to show the trend in magnitude over time. This appears to be independent of summer/winter effects in that the median increase remains high from around July through to March. Given the known role of vitamin D in winter illness [43-48], it is worthy to note that vitamin D levels are at their highest at the end of summer [49], and due to the time lags in synthesis vitamin D only drops to a minimum toward the end of winter. Hence the effect seen in Figure 8 probably reflects the higher outbreak potential which would be expected in the mid-point of any outbreak.

Figure 8. Median value of the 2009/10 step-increase (size-adjusted), proportion initiating, and month of initiation

Discussion

This study builds upon three previous small area studies where the geographic areas are all within the larger area covered by a single acute site, by a single PCO and by a single social services [21-24,26-27]. The observed behavior therefore cannot be attributed to differences in acute thresholds to admission, PCO policies or practices, or to the funding of social services. Likewise differences in weather can be excluded - the geographies are simply far too close to each other to experience significant differences in weather-related variables.

The potential contribution of poor hospital care to the related increase in deaths which appears to accompany these events, can be categorically excluded on the basis that Hospital Standardized Mortality Rates (HSMR) at the Wigan Royal Infirmary were below average during the period of this study. As expected, there was a slight wobble in the HSMR during the one to two month period where deaths initially lag behind rising admissions.

A similar range in the dates for the maximum and minimum values of medical admissions seen in Table S1, has also been observed in Berkshire (south of England) for the same date range used in this study [22,26,27].The key difference between these two locations appears to lie in the fact that the 2010 event seems to have had a far greater effect in Wigan than in Berkshire, while the reverse seems true for the 2012 event.

Most of the LSOA in Wigan are not subject to large population changes, and hence underlying growth is not large. The value of the calculated step-like changes shown in Figure 3 should therefore not require any growth adjustment.

A single clear step-increase would generate a ramp with little variation in slope over the ensuing 365 day period. From Figure 2 it is clear that the resulting ramp-like trends are more complex. From the perspective of disease transmission along social networks [29-31,50,51], an LSOA containing around 1,500 people is still a relatively large area, and given the implied relatively slow spread of the agent (i.e. relatively difficult to transmit) such complex time-trends are to be expected.

It must be recalled that a series of outbreaks at roughly two year intervals is an unprecedented situation since only two events per decade are most common [18]. Given that each event takes roughly two years to spread across the entire UK [18], it is therefore unsurprising that in some LSOA, late occurrences of the 2008 event can merge with the 2010 event and likewise with the 2010 and 2012 events. It has already been observed that spread occurs across the entire UK, and the member states of the European Union during an approximate two year window [15]. Similar dates and rate of spread have been observed in Australia [41] and New Zealand (in preparation). This wider spread precludes common health policy and funding since the four countries of the UK all operate different health policies and practices, as do the member countries of the European Union, while Australia and New Zealand are in the southern hemisphere.

The relationship between size and the apparent increase due to the step-like changes seen in Figure 3 has also been documented in Berkshire, and appears to arise from relatively slow spread of the agent within geographic areas containing different sized populations [22]. This is partly an expression of the Modifiable Areal Unit Problem (MAUP), and arises due to the slow spread within the different sized areas such that in larger areas there is greater opportunity for periods of maximum and minimum admissions within the constituent smaller areas to cancel each other out thereby reducing the value of the apparent step-increase [22]. This effect is illustrated in Table S2 (Supplementary material) where the step-increase is always greater for the LSOA within each MSOA than that for the MSOA.

A range of medical conditions are most affected, with a common linkage appearing to be related to immune function, i.e. infection, inflammation and autoimmunity [13,14,16,17]. In terms of increased death, the group of persons most dramatically affected by these events appears to be those suffering from existing neurological disorders, especially Alzheimer’s, dementia and Parkinson’s [52,53]. The very high prevalence of chronic fatigue, induced by peripheral inflammation and immune activation in this group, further emphasizes the potential pivotal role of immune dysfunction in susceptibility to these events [54].

Based on the range of conditions showing the greatest increase in admissions and deaths during these events, the ubiquitous immune-modifying persistent herpes virus, cytomegalovirus, has been implicated as either the causative agent or as secondary involvement by opportunistic reactivation in the presence of another agent [12-41,39,55-57]. Further work is required to validate this observation.

Factors influencing the increase in admissions

While population density has been shown to influence factors such as ambulance workload [58], the absence of a role for this factor in this study is not unexpected. This is because population density in Wigan is not high, and the maximum population density of 90 persons per hectare is only 14% of the maximum LSOA population density observed in London. At such low densities it is the social networks which will determine the degree of transmission [50,51]. Likewise deprivation using the IMD has been shown to influence health inequalities [59], however on this occasion it does not appear to be a major factor in transmission. From the evidence available, age appears to have the strongest factor influencing the percentage increase in admissions. Numerous studies have suggested that transmission of influenza-like illness depends mainly on contact with children who are the principal carriers [60,61], and it is contact with their elderly relatives which provides the opportunity for increased hospital admission among this age group. This risk of admission is then modified by the previous antibody history of the person to different strains of the agent [62].

Uncertainty in the initiation date

As has been discussed, two different methods were used to estimate the start of the 2009/10 event in each location. Hence either step-up or step-down or the method which assumes that step-down occurs 365 days after step-up and averages the value of the two events. In selecting the date for the maximum step-change it was noted that the maximum percentage change (to one decimal place accuracy) often occurred over a two to ten day range. For consistency the earliest date in this range was recorded as the start date. All methods detect the point of maximum 365 day change and therefore probably detect the point at which mass action has occurred, with actual arrival of the agent probably occurring days or weeks earlier. The resulting estimate of the (mass action) initiation date are listed in Table S2. Hence Wigan 001A has 17th October 2009 from all three estimates while Wigan 003A ranges from 1st Mar (from step-down) to 24th May (combined step-up/step-down). The assumption is that the event lasts for exactly 365 days, which may not always be the case. Table S2 also lists the time difference between step-up and step-down, and there is the possibility that a shorter duration than 365 days may be possible in some circumstances. This apparent duration could well be a function of the speed of transmission along the smaller social networks within each small area. Further work and mathematical modelling is required to clarify this issue.

The particular shape of the 2009/10 event for deaths

Given the detail now available from this study regarding the timing of the 2009/10 spatial spread throughout Wigan, the peculiar shape of the running 12 month total deaths in Figure 1 relating to the 2009/10 event can be explained. As has been explained a running 12 month total reveals the onset of a step-like increase in deaths or admissions observed as a ramp-up, and if this step endures for 12 months before abating, the running total then generates another ramp-down. This leads to an inverted ‘V’ shape in the running total. The base of the inverted ‘V’ should be 24 months wide. For the whole of Wigan the shape of the inverted ‘V’ can become corrupted if the underlying spatial spread of the agent is slow or patchy. The corrupted inverted ‘V’ in Figure 1 does however have a base which is 24 months wide from Jan-10 to Jan-12. In this study, the widest possible small area spread of the agent throughout Wigan has been shown to occur between Oct-08 to Apr-11 (Figure 4 – which used both step-up and step-down), while Figure 8 (which employed a method identifying greatest area under the inverted ‘V’ within a moving 24 month window) identified three periods of slightly higher spread over a more limited time period. Hence for whatever reason the 2009/10 event showed a high level of overlapping rectangular wave movement at small area level, the height of these wave being very different from one small area to another (Figure 7), all of which led to a corrupted inverted ‘V’ shape in Figure 1. It can only be assumed that similar slow and patchy spread across the whole of the UK lead to the 2009/10 event barely registering a 2% step-change, while the 2012 event shows a 5% step and the 2014 event shows a 9% step. The cluster of initiating events seen in Figure 4 around Mar-12 for the 2012 event suggests that particular events may spread faster than others, and this would lead to the range of inverted ‘V’ shaped running totals seen in Figure 1.

Why have the events been overlooked?

While it is not common to study medical admissions using very small area geographies, the considerable variation noted in this study would have resulted in great confusion to anyone attempting such analysis. Lacking knowledge of a potential infectious etiology, it is assumed that any researchers who attempted such analysis abandoned further study on the assumption that the apparently confusing results were simply due to statistical randomness or to errors in coding or data capture. The reliance on accurate patient information to trigger payment from the PCO to the hospital, excludes poor coding or data capture as an explanation for the trends seen in this study. Indeed neither coding nor data capture could account for the spatial spread between small areas.

Effect on NHS Operational Efficiency and Finances

These outbreaks pose considerable challenges in the area of health care finances and capacity planning at smaller local levels where there is considerable variation (see Figure 2 and Tables S1 and S2) [13,15,19]. However at the macro level observed by the national policy makers, the effect at larger geographies is considerably dampened, and this partly explains why these events have been overlooked for such a long time. This dampening effect is even greater using national rather than regional data, and hence wider spread across Europe also remained undetected [15], since surveillance methodologies tend to search for larger events concentrated over a shorter period of time such as an influenza epidemic or extremes of heat or cold.

If these events are as significant as they appear to be from this study their effect should be felt across the entire NHS. In this respect spatial spread of increased hospital bed occupancy has been demonstrated for the 2002/03 and 2007/08 events [63], while a more recent study on bed occupancy for the whole of England demonstrated step-like increases in average occupancy for the 2009/10, 2012/13 and 2014/15 events [64]. At £300 per bed day it was estimated that the sudden increase in occupancy for the 2014/15 event led to a cost shock of around $121 million [64].

Indeed cycles in surplus and deficit have been documented in both the US health insurance industry and the NHS, where the start of the deficit part of the cycle appears to commence with the onset of these events [15,18,65-68]. A study using NHS emergency activity grouped into Healthcare Resource Groups (HRGs), the financial currency used in the NHS, showed a clear cycle in costs of around £600 million from trough to peak which was initiated by the 2002/03 and 2007/08 outbreaks [69]. The 2007/08 outbreak lead to a 6% to 36% increase in GP referrals to particular specialties observed at Health Board and PCO level across Scotland, Wales and England [20], which was age specific.

While there is now abundant evidence for the existence and impact of these events, sadly policy makers in the UK appear to wish to continue to blame the NHS for ‘inefficiency’ rather than acknowledge that a unique infectious event may be the real cause of the higher than expected long-term increase in medical admissions [15,70].Indeed the large movements in admission implied by these events appear to be the fundamental source of year-to-year financial instability in the NHS [71-80].

Future Research

While this study has documented the small-area spatiotemporal behavior of medical admissions in some detail it raises a host of questions, such as:

  1. What percentage of the increased admissions are related to persons in the last year of life?
  2. Do the events increase the number of persons admitted and/or the number of readmissions per person?
  3. What mechanisms underly the one year duration of the increased admissions?
  4. To what extent is diagnostic ambiguity increased during these events?
  5. Are there a set of biochemical or immune parameters which characterize those who are infected with the agent?

Hopefully further prospective and retrospective studies can answer some of these questions.

Conclusion

A series of events involving relatively slow spatial spread are clearly evident at small area level in Wigan and elsewhere in the UK. A powerful infectious-like agent is implicated which leads to large increases in medical admissions (and deaths) which endure for a period of around 12 months before abating. The size of the increase in medical admissions is more readily apparent in smaller population groups presumably because a large proportion of the population are infected at roughly the same time. Urgent research is required to identify the causative agent, and to model these outbreaks. Indeed any agent capable of a sudden and sustained (size-adjusted) 50% increase in medical admissions needs to be given the utmost priority.

Acknowledgements

The permission of the Wrightington, Wigan and Leigh NHS Foundation Trust to publish this work is acknowledged. Opinions expressed in this study are exclusively those of the author.

Funding

There are no sources of funding.

Competing Interests

The author is not aware of any competing interests.

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Editorial Information

Editor-in-Chief

Bianciardi Giorgio
University of Siena

Article Type

Research Article

Publication history

Received date: August 14, 2015
Accepted date: August 22, 2015
Published date: August 24, 2015

Copyright

©2015 Jones RP. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation

Jones RP (2015) Small area spread and step-like changes in emergency medical admissions in response to an apparently new type of infectious event. Fractal Geometry and Nonlinear Anal in Med and Biol 1: doi: 10.15761/FGNAMB.100110

Corresponding author

Rodney P Jones

Healthcare Analysis & Forecasting, Camberley, UK, Tel: +44(0)1276 21061.

E-mail : hcaf_rod@yahoo.co.uk

Table S1: Details for the 100 largest areas/LSOA used in this study

Location or LSOA

Average admissions

Maximum admissions

Minimum admissions

Range as percentage of average

Running 365 day Maximum

Running 365 day Minimum

Max-Min (years)

Maximum Step-Increase

Maximum Step-Decrease

± 1 Standard Deviation (Poisson)

Start of largest step-increase

All locations

19,420

20,436

18,313

11%

29-Sep-10

31-Jan-12

-1.3

4%

9%

1%

31-Jan-12

Wigan

17,291

18,194

16,342

11%

29-Sep-10

31-Jan-12

-1.3

4%

9%

1%

13-Nov-11

Not Wigan

2,129

2,286

1,937

16%

29-Sep-10

31-Jan-12

-1.3

14%

15%

2%

01-Jun-09

W. Lancashire

672

718

605

17%

14-Jan-13

07-Feb-12

0.9

18%

14%

4%

15-Jan-12

Unknown

654

737

462

42%

07-Apr-11

03-Apr-09

2.0

39%

13%

4%

13-Jun-09

Wigan 031E

333

385

259

38%

14-Jan-11

04-Feb-12

-1.1

41%

31%

5%

04-Feb-12

St. Helens

293

336

252

29%

20-Jul-09

01-Mar-11

-1.6

20%

23%

6%

22-Apr-11

Wigan 015D

256

345

197

58%

16-Jan-10

08-Jul-12

-2.5

17%

35%

6%

20-Mar-12

Other UK

241

303

171

55%

06-Nov-09

24-Jul-12

-2.7

10%

31%

6%

30-Mar-12

Wigan 009C

224

277

189

39%

09-Feb-10

24-Feb-12

-2.0

12%

22%

7%

11-Apr-09

Wigan 035A

205

245

159

42%

18-May-11

11-Jun-10

0.9

48%

29%

7%

11-Jun-10

Wigan 010C

196

248

175

37%

19-Jul-09

26-Nov-10

-1.4

15%

25%

7%

26-Nov-10

Wigan 014B

193

222

163

31%

22-Oct-10

12-Sep-11

-0.9

34%

25%

7%

18-Mar-12

Wigan 033E

190

241

150

48%

18-Apr-09

21-Dec-11

-2.7

40%

23%

7%

21-Dec-11

Wigan 015B

186

221

153

37%

27-Apr-11

28-Jul-10

0.7

43%

26%

7%

28-Feb-10

Wigan 016E

174

200

137

36%

23-Apr-11

25-Jan-13

-1.8

23%

28%

8%

04-Apr-09

Wigan 032D

167

204

131

44%

13-Oct-10

22-Mar-13

-2.4

31%

30%

8%

20-Jun-09

Wigan 015C

166

192

142

30%

30-Jun-11

11-Jan-10

1.5

25%

19%

8%

12-Jan-10

Wigan 010D

163

223

114

67%

12-Nov-10

11-Apr-09

1.6

77%

43%

8%

16-Nov-09

Wigan 009A

162

195

132

39%

14-Aug-10

21-Jun-12

-1.9

23%

28%

8%

19-Jun-09

Wigan 012B

159

176

134

26%

06-Jun-09

17-Sep-12

-3.3

14%

16%

8%

13-Feb-11

Wigan 015E

156

190

127

40%

24-Aug-09

05-Dec-12

-3.3

9%

23%

8%

03-Apr-09

Wigan 012C

156

182

132

32%

09-Nov-09

31-Mar-13

-3.4

21%

23%

8%

05-Jan-11

Wigan 010B

153

191

130

40%

07-Jun-10

02-Jun-12

-2.0

36%

30%

8%

16-May-09

Wigan 013C

152

181

106

49%

26-Feb-10

16-Dec-11

-1.8

44%

39%

8%

28-Dec-11

Wigan 036C

152

175

128

31%

24-May-12

14-May-10

2.0

26%

23%

8%

20-Mar-10

Wigan 024B

150

184

118

44%

24-May-09

26-Sep-11

-2.3

27%

33%

8%

22-Aug-11

Wigan 027D

148

170

119

34%

09-Dec-09

08-Dec-12

-3.0

24%

27%

8%

20-Sep-10

Wigan 012D

147

198

96

69%

26-May-09

28-Nov-12

-3.5

5%

36%

8%

29-Nov-10

Wigan 010A

143

168

121

33%

02-Aug-09

26-Jan-13

-3.5

16%

21%

8%

04-Jul-10

Wigan (small)

143

170

125

31%

27-Nov-09

13-Sep-12

-2.8

17%

24%

8%

08-Jun-09

Wigan 036A

142

175

114

43%

16-Jun-12

31-Oct-10

1.6

32%

20%

8%

07-Nov-10

Wigan 016A

141

161

111

35%

13-Dec-09

23-Oct-12

-2.9

14%

26%

8%

29-Apr-09

Wigan 040D

140

189

101

63%

21-Nov-12

31-Mar-09

3.6

55%

23%

8%

27-Dec-11

Wigan 007B

140

169

105

46%

03-Sep-09

22-Apr-12

-2.6

23%

37%

8%

09-Jul-10

Wigan 012A

140

182

100

59%

17-Sep-10

08-Jan-13

-2.3

33%

36%

8%

14-Sep-09

Wigan 006B

137

157

115

31%

26-Dec-09

23-Mar-12

-2.2

33%

20%

9%

28-Mar-12

Wigan 013B

134

159

104

41%

09-Jun-10

04-Jun-12

-2.0

46%

23%

9%

26-Mar-12

Wigan 008C

133

163

114

37%

24-Oct-10

03-Apr-09

1.6

38%

28%

9%

19-Sep-09

Bolton

132

162

104

44%

11-Feb-12

10-Apr-11

0.8

49%

25%

9%

13-Apr-11

Wigan 038D

130

144

107

28%

30-Oct-10

12-Mar-13

-2.4

19%

21%

9%

21-Oct-09

Wigan 009B

129

144

108

28%

18-Jan-11

04-Apr-12

-1.2

13%

24%

9%

17-Aug-10

Wigan 024C

128

143

111

25%

15-Oct-10

07-Apr-09

1.5

22%

18%

9%

13-Oct-09

Wigan 027A

127

165

85

63%

17-Dec-09

06-Nov-12

-2.9

18%

38%

9%

30-Mar-12

Wigan 036B

127

149

100

39%

11-May-10

17-May-12

-2.0

29%

28%

9%

26-Oct-09

Wigan 002A

126

152

98

43%

11-Sep-10

05-Nov-12

-2.2

13%

24%

9%

12-Sep-09

Wigan 009D

126

204

95

87%

13-Dec-12

04-Jun-09

3.5

95%

17%

9%

04-Jun-09

Wigan 005B

124

149

98

41%

25-Aug-10

06-Sep-09

1.0

52%

22%

9%

06-Sep-09

Wigan 016B

123

160

90

57%

10-Feb-12

31-Mar-09

2.9

31%

34%

9%

10-Feb-11

Wigan 010E

123

161

106

45%

09-May-09

13-May-12

-3.0

14%

29%

9%

08-Jan-10

Wigan 018B

119

141

93

40%

19-Jul-11

16-Jul-12

-1.0

30%

34%

9%

12-May-10

Wigan 014D

119

139

103

30%

02-Apr-09

11-Feb-12

-2.9

26%

19%

9%

11-Feb-12

Wigan 002E

118

143

98

38%

01-Apr-09

25-Jan-12

-2.8

27%

22%

9%

07-Feb-12

Wigan 009E

117

128

98

26%

19-Jan-10

20-Nov-10

-0.8

21%

23%

9%

20-Nov-10

Wigan 013A

116

133

89

38%

02-Sep-11

04-Jun-10

1.2

40%

31%

9%

01-Aug-10

Wigan 005E

115

130

101

25%

23-Aug-10

11-Nov-11

-1.2

18%

22%

9%

11-Jul-11

Wigan 019C

115

136

97

34%

23-Jan-11

12-Apr-12

-1.2

21%

27%

9%

23-Jan-10

Wigan 024A

115

136

97

34%

04-Jan-10

07-Jun-11

-1.4

26%

24%

9%

07-Jun-11

Wigan 011E

113

135

86

43%

17-Jan-11

15-Feb-13

-2.1

13%

32%

9%

03-Jun-10

Wigan 008B

113

136

95

36%

12-Sep-11

09-Mar-13

-1.5

33%

27%

9%

22-Mar-10

Wigan 016C

113

137

96

36%

20-Oct-09

18-Jul-12

-2.7

17%

22%

9%

25-Jan-11

Wigan 027C

112

137

89

43%

11-Apr-09

22-Nov-10

-1.6

31%

27%

9%

03-Aug-11

Wigan 006E

109

133

85

44%

02-Mar-11

23-Dec-11

-0.8

40%

35%

10%

23-May-10

Wigan 004D

109

127

90

34%

10-Apr-11

09-Apr-12

-1.0

30%

29%

10%

10-Apr-10

Wigan 018C

108

126

98

26%

20-Jul-11

03-Aug-10

1.0

27%

18%

10%

20-Jul-10

Wigan 015A

108

149

83

61%

29-Mar-10

22-Apr-11

-1.1

42%

43%

10%

09-Apr-09

Wigan 006A

107

136

77

55%

18-Jan-10

19-Feb-13

-3.1

34%

34%

10%

30-Aug-11

Wigan 014A

105

125

84

39%

13-Jul-10

13-Jul-11

-1.0

37%

33%

10%

13-Jul-11

Wigan 003D

104

151

66

82%

14-Dec-10

16-Dec-11

-1.0

54%

56%

10%

06-Oct-09

Wigan 011B

104

141

83

56%

10-Mar-13

03-Apr-12

0.9

63%

26%

10%

16-Mar-12

Wigan 026E

104

140

67

70%

30-Mar-10

26-Feb-13

-2.9

58%

34%

10%

31-Mar-09

Wigan 020C

103

137

76

59%

13-Sep-10

03-Aug-12

-1.9

57%

32%

10%

16-Sep-09

Wigan 005A

102

120

84

35%

22-Dec-10

28-Dec-09

1.0

43%

23%

10%

28-Dec-09

Wigan 001C

101

118

86

32%

19-Jan-11

01-Jun-10

0.6

31%

23%

10%

03-Mar-10

Wigan 011A

101

118

82

36%

21-Jun-10

14-Nov-12

-2.4

23%

29%

10%

04-Jul-11

Wigan 030B

99

122

74

48%

25-Aug-10

19-Oct-11

-1.2

49%

37%

10%

23-Nov-11

Wigan 033B

99

119

79

40%

28-Jan-10

30-Mar-13

-3.2

21%

22%

10%

02-Aug-11

Wigan 002C

98

120

74

47%

18-Feb-11

23-Jun-09

1.7

34%

24%

10%

13-Feb-10

Wigan 011C

98

133

78

56%

31-Mar-09

19-Dec-11

-2.7

41%

40%

10%

25-Apr-10

Wigan 007D

97

126

72

55%

03-Jul-10

20-Aug-11

-1.1

40%

38%

10%

05-Oct-11

Wigan 018E

97

114

84

31%

18-Oct-12

07-Apr-09

3.5

33%

21%

10%

19-Oct-11

Wigan 019A

96

113

69

46%

18-Sep-12

07-Nov-10

1.9

62%

32%

10%

10-Nov-10

Wigan 013D

94

122

68

57%

09-Apr-09

09-Jul-10

-1.2

63%

42%

10%

10-Jul-10

Wigan 038E

93

114

69

48%

28-Jan-11

04-Jul-09

1.6

48%

32%

10%

05-Feb-10

Wigan 038C

93

115

74

44%

16-May-11

06-Jan-10

1.4

52%

28%

10%

13-Feb-10

Wigan 032C

92

112

68

48%

28-Aug-12

13-May-09

3.3

31%

19%

10%

13-May-09

Wigan 020A

92

103

75

30%

26-Feb-10

31-Mar-09

0.9

37%

20%

10%

01-Apr-09

Wigan 033D

92

113

61

57%

22-Feb-13

03-Apr-09

3.9

56%

30%

10%

25-Jun-09

Wigan 027B

92

109

70

43%

21-Jun-11

08-Apr-10

1.2

51%

22%

10%

08-Apr-10

Wigan 012E

92

110

76

37%

07-Jun-11

04-Mar-13

-1.7

26%

23%

10%

15-Jun-10

Wigan 024D

91

100

80

22%

05-May-11

05-May-10

1.0

25%

16%

11%

30-May-10

Wigan 014C

88

121

65

63%

23-Dec-10

19-Jul-09

1.4

82%

41%

11%

13-Oct-09

Wigan 026D

88

103

73

34%

23-Oct-09

21-Dec-11

-2.2

41%

20%

11%

21-Dec-11

Wigan 032A

88

108

73

40%

31-Mar-13

22-Jan-11

2.2

33%

24%

11%

23-Apr-11

Wigan 032E

87

103

67

41%

05-Jun-11

04-Apr-09

2.2

37%

24%

11%

04-Apr-09

Wigan 031A

86

126

63

73%

05-Mar-11

06-Mar-10

1.0

100%

39%

11%

06-Mar-10

Wigan 018A

86

123

65

68%

14-Jul-11

29-Nov-09

1.6

68%

46%

11%

20-Jun-10

Wigan 014E

85

107

67

47%

28-Nov-12

25-Sep-10

2.2

37%

26%

11%

01-Dec-11

Wigan 037B

85

106

63

51%

30-Nov-10

29-Nov-11

-1.0

50%

40%

11%

03-Jan-12

Wigan 026C

83

109

66

52%

21-Aug-10

11-Sep-12

-2.1

50%

35%

11%

08-Apr-09

 

 

 

 

 

 

 

 

 

 

 

Table S2: Details of the largest step-u and step-down, plus the 2009/10 event for MSOA and associated LSOA within each of these MSOA

Location

Admissions per 365 days

Largest step-up or step-down

2009/10 Event

Maximum

Minimum

Average (Apr-08 to May-12)

Average (Mar-09 to Feb-11)

Range (max - min)

Step-up

Step-down

85% CI (Poisson)

Start Up

Start Down

Differ-ence (years)

Ratio Max up/down

Start of event

Average Step-change

Adjusted to 100 deaths equivalent

All areas

20,436

18,313

19,420

19,947

11%

4%

10%

1%

31-Jan-12

23-Oct-10

-1.3

37%

29-Sep-09

6%

89%

Wigan

18,194

16,342

17,291

17,769

11%

3%

10%

1%

13-Nov-11

23-Oct-10

-1.1

36%

29-Sep-09

6%

85%

Not Wigan

2,286

1,937

2,129

2,179

16%

13%

16%

2%

1-Jun-09

28-Mar-11

1.8

79%

28-Mar-10

10%

48%

W. Lancashire

718

605

672

686

17%

16%

15%

4%

15-Jan-12

19-Feb-11

-0.9

107%

3-Mar-10

10%

26%

Unknown

737

462

654

618

42%

29%

15%

4%

13-Jun-09

8-Apr-11

1.8

193%

7-Apr-10

15%

39%

Bolton

162

104

132

127

44%

39%

30%

9%

13-Apr-11

28-Jan-12

0.8

128%

10-Apr-09

9%

11%

Chorley

69

36

53

58

62%

43%

55%

14%

11-Jun-11

11-Feb-10

-1.3

79%

10-May-09

26%

19%

Other

303

171

241

278

55%

11%

33%

6%

30-Mar-12

20-Jun-11

-0.8

34%

25-Jun-09

14%

22%

St. Helens

336

252

293

305

29%

17%

25%

6%

22-Apr-11

1-Mar-10

-1.1

68%

8-Apr-09

9%

15%

Warrington

45

12

30

37

110%

56%

56%

18%

12-Apr-09

20-Dec-11

2.7

100%

23-Apr-09

53%

29%

Wigan (small)

170

125

143

147

31%

15%

28%

8%

8-Jun-09

28-Nov-09

0.5

55%

13-Jul-09

15%

18%

Wigan 001A

109

54

72

81

76%

65%

68%

12%

17-Oct-09

17-Oct-10

1.0

96%

17-Oct-09

66%

56%

Wigan 001B

74

34

56

66

71%

50%

52%

13%

3-Mar-12

26-Feb-11

-1.0

97%

1-Apr-09

23%

17%

Wigan 001C

118

86

101

100

32%

28%

25%

10%

3-Mar-10

1-Jun-09

-0.8

112%

3-Mar-10

25%

25%

Wigan 001D

57

29

41

36

68%

51%

51%

16%

19-Jul-10

23-Dec-11

1.4

100%

18-May-10

34%

22%

Wigan01

325

235

270

282

33%

24%

30%

6%

16-Oct-09

23-Oct-10

1.0

79%

23-Oct-09

27%

45%

Wigan 002A

152

98

126

138

43%

14%

28%

9%

12-Sep-09

28-Nov-10

1.2

50%

28-Nov-09

19%

21%

Wigan 002B

76

48

62

64

45%

35%

45%

13%

1-Oct-09

7-Oct-10

1.0

79%

1-Oct-09

39%

31%

Wigan 002C

120

74

98

93

47%

31%

30%

10%

13-Feb-10

18-Feb-11

1.0

103%

18-Feb-10

30%

30%

Wigan 002D

76

40

52

48

70%

66%

21%

14%

1-Nov-11

3-Oct-10

-1.1

309%

3-Oct-09

16%

12%

Wigan 002E

143

98

118

124

38%

22%

24%

9%

7-Feb-12

5-Feb-11

-1.0

93%

5-Feb-10

16%

18%

Wigan02

502

401

457

467

22%

19%

20%

5%

21-Feb-12

23-Feb-11

-1.0

97%

25-Feb-10

15%

32%

Wigan 003A

91

60

76

82

41%

20%

32%

11%

29-Dec-11

1-Mar-10

-1.8

63%

24-May-09

22%

19%

Wigan 003B

98

56

78

88

54%

30%

36%

11%

11-Feb-12

6-Sep-10

-1.4

82%

6-Sep-09

20%

18%

Wigan 003C

96

61

76

78

46%

22%

46%

11%

12-Oct-10

11-Oct-09

-1.0

49%

11-May-10

8%

7%

Wigan 003D

151

66

104

119

82%

50%

82%

10%

6-Oct-09

15-Dec-10

1.2

61%

17-Dec-09

65%

67%

Wigan 003E

98

64

77

81

44%

25%

34%

11%

22-Feb-11

10-Oct-09

-1.4

73%

1-Apr-09

8%

7%

Wigan 003F

68

33

47

39

75%

47%

19%

15%

22-Aug-10

31-Mar-09

-1.4

244%

28-Feb-10

18%

12%

Wigan 003G

80

26

58

72

94%

33%

74%

13%

14-Mar-12

15-Jun-11

-0.7

44%

12-Nov-09

44%

34%

Wigan03

584

430

516

559

30%

11%

26%

4%

11-Dec-11

14-Dec-10

-1.0

44%

14-Dec-09

14%

31%

Wigan 004A

101

58

78

67

55%

47%

15%

11%

3-Nov-10

27-Feb-12

1.3

308%

13-Jun-10

20%

18%

Wigan 004B

101

60

81

82

51%

28%

49%

11%

9-Jan-12

1-Dec-09

-2.1

58%

24-May-10

7%

6%

Wigan 004C

99

59

77

71

52%

47%

35%

11%

3-Mar-11

30-Mar-12

1.1

133%

31-Mar-09

18%

16%

Wigan 004D

127

90

109

109

34%

27%

34%

10%

10-Apr-10

10-Apr-11

1.0

78%

10-Apr-10

30%

32%

Wigan04

389

302

345

329

25%

21%

18%

5%

3-Nov-10

12-Jul-09

-1.3

121%

29-Apr-10

6%

11%

Wigan 005A

120

84

102

103

35%

35%

27%

10%

28-Dec-09

28-Dec-10

1.0

133%

28-Dec-09

31%

31%

Wigan 005B

149

98

124

122

41%

41%

27%

9%

6-Sep-09

4-Sep-10

1.0

155%

4-Sep-09

33%

37%

Wigan 005C

92

60

74

76

43%

34%

42%

12%

29-Mar-12

5-Jul-09

-2.7

81%

5-Apr-10

17%

15%

Wigan 005D

96

43

75

77

71%

48%

61%

12%

6-Sep-09

27-Feb-12

2.5

78%

31-Dec-09

28%

24%

Wigan 005E

130

101

115

119

25%

17%

24%

9%

11-Jul-11

27-Aug-10

-0.9

68%

30-Aug-09

20%

21%

Wigan05

552

452

490

498

20%

17%

15%

5%

29-Dec-09

19-Sep-10

0.7

109%

17-Sep-09

16%

35%

Wigan 006A

136

77

107

122

55%

25%

38%

10%

30-Aug-11

15-Sep-10

-1.0

66%

25-Jul-09

16%

17%

Wigan 006B

157

115

137

141

31%

28%

22%

9%

28-Mar-12

29-May-10

-1.8

127%

1-Jun-09

20%

24%

Wigan 006C

98

42

69

80

81%

45%

55%

12%

30-Sep-09

20-Oct-10

1.1

82%

5-Oct-09

47%

39%

Wigan 006D

102

47

76

85

73%

53%

49%

11%

17-Feb-12

4-Jan-11

-1.1

108%

4-Jan-10

26%

23%

Wigan 006E

133

85

109

113

44%

33%

42%

10%

23-May-10

23-Dec-10

0.6

78%

23-Dec-09

34%

35%

Wigan06

564

413

498

541

30%

12%

26%

4%

2-Jan-12

7-Jan-11

-1.0

47%

16-Sep-09

14%

32%

Wigan 007A

89

52

70

69

53%

45%

32%

12%

26-Aug-11

25-Aug-10

-1.0

141%

18-May-09

24%

20%

Wigan 007B

169

105

140

152

46%

21%

44%

8%

9-Jul-10

19-Mar-11

0.7

48%

19-Mar-10

29%

35%

Wigan 007C

59

28

42

47

74%

14%

40%

15%

1-Dec-11

30-Jan-11

-0.8

35%

6-Mar-10

23%

15%

Wigan 007D

126

72

97

109

55%

30%

48%

10%

5-Oct-11

20-Aug-10

-1.1

62%

4-Jul-09

36%

36%

Wigan007

398

281

349

378

34%

19%

27%

5%

2-Dec-11

2-Dec-10

-1.0

72%

4-Jan-10

13%

24%

Wigan 008A

90

57

74

80

44%

13%

24%

12%

10-Aug-09

30-Nov-09

0.3

56%

10-Aug-09

17%

15%

Wigan 008B

136

95

113

112

36%

28%

32%

9%

22-Mar-10

20-Sep-11

1.5

89%

18-Feb-10

24%

26%

Wigan 008C

163

114

133

136

37%

34%

35%

9%

19-Sep-09

22-Oct-10

1.1

98%

27-Oct-09

33%

38%

Wigan 008D

91

62

76

77

38%

34%

29%

11%

6-Sep-11

18-May-10

-1.3

118%

2-Oct-09

21%

18%

Wigan 008E

92

52

70

71

57%

53%

38%

12%

16-Nov-09

3-Sep-11

1.8

137%

11-Apr-10

41%

35%

Wigan008

528

434

467

476

20%

19%

17%

5%

5-Nov-09

22-Dec-10

1.1

113%

2-Nov-09

17%

37%

Wigan 009A

195

132

162

174

39%

22%

34%

8%

19-Jun-09

16-Aug-10

1.2

64%

16-Aug-09

27%

35%

Wigan 009B

144

108

129

132

28%

12%

26%

9%

17-Aug-10

5-Apr-11

0.6

47%

5-Apr-10

19%

21%

Wigan 009C

277

189

224

244

39%

13%

26%

7%

11-Apr-09

22-Apr-10

1.0

47%

22-Apr-09

19%

28%

Wigan 009D

204

63

126

97

112%

68%

16%

9%

4-Jun-09

17-Mar-10

0.8

430%

25-May-09

31%

35%

Wigan 009E

128

98

117

114

26%

18%

25%

9%

20-Nov-10

20-Nov-09

-1.0

72%

21-May-10

6%

6%

Wigan009

810

699

756

761

15%

14%

9%

4%

19-Jan-12

24-Mar-10

-1.8

146%

27-May-09

10%

27%

Wigan 010A

168

121

143

148

33%

15%

24%

8%

4-Jul-10

4-Aug-09

-0.9

60%

17-May-10

7%

8%

Wigan 010B

191

130

153

169

40%

33%

38%

8%

16-May-09

11-Jun-10

1.1

86%

7-Jun-09

33%

41%

Wigan 010C

248

175

196

204

37%

13%

32%

7%

26-Nov-10

2-Aug-09

-1.3

42%

30-Jan-10

8%

12%

Wigan 010D

223

114

163

165

67%

59%

56%

8%

16-Nov-09

8-Jan-11

1.1

105%

12-Nov-09

57%

73%

Wigan 010E

161

106

123

132

45%

13%

38%

9%

8-Jan-10

16-May-09

-0.6

35%

8-Jan-10

15%

16%

Wigan010

863

703

778

818

21%

12%

19%

4%

27-Dec-09

11-Jan-11

1.0

66%

8-Jan-10

15%

43%

Wigan 011A

118

82

101

109

36%

19%

34%

10%

4-Jul-11

28-Jun-10

-1.0

56%

21-Jun-09

22%

22%

Wigan 011B

141

83

104

104

56%

52%

31%

10%

16-Mar-12

22-Jan-10

-2.1

169%

13-Sep-09

13%

13%

Wigan 011C

133

78

98

101

56%

33%

54%

10%

25-Apr-10

31-Mar-09

-1.1

60%

22-Mar-10

32%

31%

Wigan 011D

78

58

66

68

30%

15%

23%

12%

3-Jul-10

21-Jun-09

-1.0

67%

31-May-10

11%

9%

Wigan 011E

135

86

113

122

43%

13%

37%

9%

3-Jun-10

7-Jan-11

0.6

36%

11-Jan-10

23%

25%

Wigan011

527

419

482

504

22%

13%

18%

5%

16-Mar-12

25-Dec-10

-1.2

75%

25-Apr-10

10%

22%

Wigan 012A

182

100

140

159

59%

32%

46%

8%

14-Sep-09

6-Nov-10

1.1

70%

8-Oct-09

38%

44%

Wigan 012B

176

134

159

166

26%

13%

18%

8%

13-Feb-11

13-Feb-10

-1.0

75%

14-Sep-09

10%

13%

Wigan 012C

182

132

156

159

32%

19%

26%

8%

5-Jan-11

9-Nov-09

-1.2

71%

13-Apr-09

11%

13%

Wigan 012D

198

96

147

170

69%

5%

39%

8%

29-Nov-10

29-Nov-11

1.0

12%

20-May-10

6%

7%

Wigan 012E

110

76

92

91

37%

25%

26%

10%

15-Jun-10

10-Mar-12

1.7

96%

7-Jun-10

25%

24%

Wigan012

801

570

694

745

33%

6%

17%

4%

11-Apr-09

9-Jan-12

2.7

33%

1-Apr-09

9%

23%

Wigan 013A

133

89

116

108

38%

33%

35%

9%

1-Aug-10

4-Jun-09

-1.2

95%

13-May-10

13%

14%

Wigan 013B

159

104

134

140

41%

37%

23%

9%

26-Mar-12

5-Jun-11

-0.8

161%

9-Jun-09

23%

27%

Wigan 013C

181

106

152

172

49%

31%

45%

8%

28-Dec-11

10-Dec-10

-1.0

68%

3-Dec-09

29%

35%

Wigan 013D

122

68

94

92

57%

46%

53%

10%

10-Jul-10

9-Jul-09

-1.0

86%

8-Jun-10

30%

29%

Wigan 013E

81

52

65

68

45%

23%

35%

12%

26-Jun-11

26-Jul-10

-0.9

65%

26-Jul-09

24%

19%

Wigan013

628

507

561

579

22%

9%

13%

4%

24-Mar-12

9-Apr-09

-3.0

67%

23-Apr-10

7%

17%

Wigan 014A

125

84

105

111

39%

30%

39%

10%

13-Jul-11

13-Jul-10

-1.0

76%

19-Oct-09

32%

33%

Wigan 014B

222

163

193

203

31%

29%

28%

7%

18-Mar-12

12-Sep-10

-1.5

102%

27-Dec-09

19%

26%

Wigan 014C

121

65

88

90

63%

60%

52%

11%

13-Oct-09

14-Apr-11

1.5

115%

23-Dec-09

49%

46%

Wigan 014D

139

103

119

120

30%

23%

22%

9%

11-Feb-12

31-Mar-08

-3.9

104%

13-Sep-09

13%

14%

Wigan 014E

107

67

85

81

47%

34%

28%

11%

1-Dec-11

19-Oct-09

-2.1

121%

18-May-09

7%

7%

Wigan014

651

526

591

606

21%

14%

18%

4%

9-Mar-12

22-Aug-10

-1.5

79%

16-Oct-09

15%

36%

Wigan 015A

149

83

108

123

61%

41%

59%

10%

9-Apr-09

22-Apr-10

1.0

69%

9-Apr-09

50%

52%

Wigan 015B

221

153

186

184

37%

36%

30%

7%

28-Feb-10

8-Feb-11

0.9

118%

27-Feb-10

31%

43%

Wigan 015C

192

142

166

160

30%

22%

22%

8%

12-Jan-10

30-Jun-11

1.5

97%

12-Jun-10

14%

18%

Wigan 015D

345

197

256

293

58%

16%

47%

6%

20-Mar-12

16-Jan-10

-2.2

34%

3-Jun-09

26%

41%

Wigan 015E

190

127

156

171

40%

10%

28%

8%

3-Apr-09

9-Mar-10

0.9

35%

3-Apr-09

17%

21%

Wigan 015

986

785

872

932

23%

6%

15%

3%

10-May-09

31-Dec-09

0.6

39%

11-May-09

10%

29%

Wigan 016A

161

111

141

151

35%

14%

27%

8%

29-Apr-09

19-Oct-11

2.5

53%

13-Feb-10

13%

15%

Wigan 016B

160

90

123

110

57%

31%

45%

9%

10-Feb-11

11-Feb-12

1.0

69%

29-Sep-09

6%

7%

Wigan 016C

137

96

113

118

36%

16%

27%

9%

25-Jan-11

20-Oct-09

-1.3

60%

2-Apr-09

10%

11%

Wigan 016D

41

21

32

35

63%

63%

54%

18%

8-Mar-12

29-Apr-10

-1.9