Results

Characteristics of the Sutton residents in the study and the matched comparison group were broadly similar

After matching, the control group was found to be broadly similar to the Sutton residents in the study across the range of individual and care home characteristics considered (see Technical Appendix for more details). Figure 2 shows that the two groups had a similar profile of existing health conditions. Mean follow-up time of a resident in the study was similar across the groups (Sutton residents: 166 days [standard deviation 134]; control: 166 days [standard deviation 127]). Mortality rates in the two groups were also the same: 82 residents died in each group during the study period.

Figure 2: Distribution of key health conditions across the Sutton residents in the study and the control residents

Table 2 compares the Sutton residents in the study, the matched control group and the full pool of potential controls at baseline. For some of these characteristics a relatively unsuccessful matching outcome was largely anticipated: for instance, the care home landscape in Sutton CCG was known to feature on average smaller care homes than other urban areas of England. Some residual difference remained between the groups, notably on:

  • care home size, age category and rural classification
  • type and number of comorbidities associated with frailty, and conditions associated with mortality (Charlson index)
  • A&E attendances
  • outpatient appointments
  • number of emergency admissions in the year before moving to a care home – both overall, and those that were potentially avoidable.

Outstanding dissimilarities at least on observable characteristics were subsequently addressed via the risk-adjusted analysis outlined in Figure 1.

Table 2: Characteristics of the study group, the matched control group and the potential control group prior to November 2015 (when enhanced support introduced in Sutton)

Baseline characteristic

Sutton residents in the study

Matched control group

Potential control group

Number of individuals

297

243

2,382

Number of records

297

296

2,382

Number of care homes

28

97

194

Resident lives in a nursing home

74.07%

74.32%

53.99%

Number of beds in the care home

29.25 (11.20)

39.19 (16.31)

40.97 (22.70)

Residing in a rural setting

<5%

<5%

11.30%

Age (in years)

85.74 (7.33)

85.83 (5.93)

85.58 (7.16)

Male

31.60%

28.40%

33.10%

White

85.50%

87.20%

88.30%

Charlson comorbidity index

2.42 (2.02)

2.10 (1.80)

1.96 (1.85)

Baseline characteristic

Sutton residents in the study

Matched control group

Potential control group

Number of frailty comorbidities recorded in the 3 years before the start of the enhanced support

2.54 (1.72)

2.30 (1.61)

1.91 (1.59)

Incontinence in the 3 years before the start of the enhanced support

17.50%

11.80%

8.60%

A&E attendances in the year before the start of the enhanced support

2.66 (2.79)

2.32 (1.85)

2.26 (2.08)

Potentially avoidable emergency admissions in the year before the start of the enhanced support

0.60 (0.76)

0.49 (0.69)

0.51 (0.83)

Hospital bed days in the year before the start of the enhanced support

42.57 (41.39)

40.14 (40.10)

36.15 (47.29)

Emergency admissions in the year before the start of the enhanced support

2.03 (1.92)

1.81 (1.46)

1.67 (1.65)

Elective admissions in the year before the start of the enhanced support

0.30 (1.12)

0.31 (0.99)

0.34 (3.32)

UTIs in the year before the start of the enhanced support

0.20 (0.47)

0.13 (0.39)

0.17 (0.47)

Outpatient appointments in the year before the start of the enhanced support

12.95 (12.32)

7.79 (12.36)

5.43 (9.84)

Outcomes excluded from the report

An analysis of the relative rates of hospital admissions with UTIs was inconclusive due to the very low numbers reported for these events, and therefore was excluded from the detailed presentation in the report.

We also observed that a considerable proportion of outpatient appointments were scheduled prior to individuals entering the care home, and so could not realistically have been influenced by the enhanced support. In the light of this observation and of the differences in outpatient appointments described in Table 2, we did not consider our findings for this outcome to be informative about the enhanced support's effectiveness; as such, we do not present them in this report.

A statistically significant difference in hospital activity was not detected

Figure 3 shows trends in hospital utilisation over time. For each chart, the horizontal x-axis represents time in the study (with quarterly increments), and entry into a care home is set at time zero. The y-axis shows the mean rate of a given outcome for each corresponding quarter for Sutton residents in the study and control group residents before and after moving to a care home (negative and positive x-axis values, respectively). As would be expected, given the matching process, both Sutton and control residents in the study experienced similar rates of hospital activity before moving into care homes (left panel within each chart), although small residual differences can be seen for some of the measures, as noted above. Comparing the right-hand side of each chart to the left-hand side shows that, after moving into a care home, rates of hospital activity are lower for both groups, and appear relatively similar between Sutton residents and controls for A&E attendances, emergency admissions and hospital bed days. In general, where rates of hospital activity appear slightly different, they are marginally higher for Sutton residents in the study than for the matched control residents, both before and after moving to a care home.

Figure 3: Comparison of Sutton and control residents in the study across selected outcome measures

Table 3 shows how the groups compared in the follow-up period. The crude rates indicate the number of events per person per year, and are not adjusted for the differences that remained between the two groups after matching. The relative differences, on the other hand, account for the remaining differences between the two groups and will therefore be referred to when drawing conclusions and interpretations from the evaluation.

In our adjusted analyses, hospital utilisation did not appear to be statistically significantly different between the Sutton residents in the study and the matched control residents on any of the reported measures: that is, A&E attendances, emergency admissions, potentially avoidable emergency admissions and hospital bed days. All 95% confidence intervals spanned 0%, indicating no significant difference between groups at a 5% significance level.

Looking at each of the measures in more detail, Sutton residents in the study experienced an average of 1.24 A&E attendances per year after moving to a care home compared with 1.15 attendances for matched control residents. After risk adjustment (see the section on 'Selecting the comparison group' on page 9 for details), a statistically significant difference in the rate of A&E attendances was not detected, with a 95% confidence interval suggesting the true difference lies in the range of 24% lower to 32% higher A&E attendances in Sutton.

There were 0.98 emergency admissions per year for Sutton residents in the study compared with 0.86 emergency admissions for matched control residents. After adjustment, 52% more emergency admissions were estimated for Sutton residents than control residents, but the relative difference could lie anywhere from 7% fewer to 150% more emergency admissions for Sutton residents.

Crude rates show that Sutton residents in the study experienced 0.5 potentially avoidable emergency admissions per person per year against 0.31 among control group residents. After risk adjustment, potentially avoidable emergency admissions were estimated to be 181% more likely for Sutton residents than for the control group, with very wide confidence intervals spanning 0%, demonstrating a high degree of uncertainty in the result.

Sutton residents in the study had 4.7 hospital bed days per year compared with 3.7 for control residents. After risk adjustment, Sutton residents had 49% more estimated hospital bed days than residents in the control group, with 95% confidence intervals suggesting a relative difference in the range of 11% fewer to 148% more hospital bed days.

Table 3: Comparison of hospital utilisation between the Sutton residents and the matched control residents

Crude rates for Sutton residents in the study (number per person per year)

Crude rates for matched control residents (number per person per year)

Relative difference from matched comparison group (adjusted rate ratio)

95% confidence interval

P-value

A&E attendances

1.24

1.15

0% (no difference)

24% lower to 32% higher for Sutton

0.997

Emergency admissions

0.98

0.86

52% higher for Sutton

7% lower to 150% higher for Sutton

0.098

Potentially avoidable emergency admissions

0.5

0.31

181% higher for Sutton

10% lower to 779% higher for Sutton

0.077

Hospital bed days (mean, standard deviation)

4.7 (11.8)

3.7 (11.2)

49% higher for Sutton

11% lower to 148% higher for Sutton

0.127

A p-value is a number between 0 and 1 and is commonly interpreted as follows: a small p-value (typically less than 0.05) indicates strong evidence of a difference in the outcome examined between Sutton residents and the control; a large p-value (greater than 0.05) offers no evidence in support of there being a difference; and p-values close to 0.05 are indicative of weak evidence of a difference and thus are subject to interpretation.

A statistically significant difference in the proportion of deaths that occurred outside hospital was not detected

During the study period, 82 of the Sutton residents in the study died, as did 82 of the matched control residents. Among the Sutton residents who died, 72% of deaths occurred outside hospital, compared with 79% of deaths for the matched control residents. After adjustment, the proportion of deaths outside hospital was 63% lower for Sutton residents in the study. The relative difference in proportion of deaths outside hospital could lie in the range of 92% lower to 40% higher in Sutton (see Table 4).

Table 4: Comparison of percentage of deaths occurring outside hospital

Sutton residents in the study

Matched control residents

Relative difference from matched comparison (adjusted odds ratio)

95% confidence interval

P-value

Percentage of deaths outside hospital (number of deaths outside hospital/total deaths)

71.95% (59/82)

79.27% (65/82)

63% lower for Sutton

92% lower to 40% higher for Sutton

0.161

The type of care home and timing of entry into a care home may affect the impact of the enhanced support

Further analyses were performed to investigate the impact of the enhanced support in specific subgroups of care home residents based on:

  • residential or nursing care home: residential (77 Sutton residents in the study, 76 control residents) vs nursing (220 residents both in Sutton and the control group)
  • timing of entry to care home: early (65 residents in Sutton, 80 residents in the control group) or late (147 residents in Sutton, 130 residents in the control group).

All of the outcome measures reported above for the overall population were also analysed in the subgroup populations. The quality of the matching process was also reassessed for the individual subgroups and was found to be equally satisfactory to the base case analysis. There were two statistically significant findings, and these are presented in Table 5 with other selected findings that support their interpretation. Note that for some of the outcomes (eg the number of emergency admissions) the crude rates for the Sutton residents are lower than those for the matched control residents, whereas the risk-adjusted rates among Sutton residents are higher than in the control group. This is not unexpected, since the crude rates do not adjust for observable differences in the characteristics of the two groups (see 'Characteristics of the Sutton residents in the study and the matched comparison group were broadly similar' on page 13) and as such offer a less reliable measure of intervention effectiveness. Results for the other outcomes not examined in the subgroup analyses were not as informative and are not included in this report (see the Technical Appendix for details).

Among nursing home residents, those in Sutton experienced 0.54 potentially avoidable emergency admissions per person per year compared with 0.26 for the corresponding matched control residents. In the risk-adjusted analysis, nursing care home residents in Sutton were estimated to be 122% more likely to experience a potentially avoidable emergency admission than those in the control nursing homes, with the confidence interval indicating a 19% to 327% greater likelihood of a potentially avoidable emergency admission in Sutton. This result was statistically significant (p=0.01). Conversely, no statistically significant difference was found in residential care home residents.

Among late care home entrants, those in Sutton had 1.28 A&E attendances per person per year, compared with 1.46 in the control care homes. In the adjusted analysis, the rate of A&E attendance was estimated to be 70% lower for late entrants to a care home in Sutton compared with late entrants to a control care home. The likelihood of an A&E attendance for late care home entrants was between 88% and 24% lower in Sutton than in the control care homes. This result was statistically significant (p=0.01).

Table 5: Selected results from subgroup analyses of the Sutton residents compared with matched control residents

Subgroup

Crude rates for new Sutton residents (number per person per year)

Crude rates for matched control residents (number per person per year)

Relative difference from matched comparison group (adjusted rate ratio)

95% confidence interval

P-value

Emergency admissions

Residential care home residents

0.96

1.18

54% higher for Sutton

34% lower to 262% higher for Sutton

0.322

Nursing care home residents

0.99

0.73

82% higher for Sutton

10% lower to 267% higher for Sutton

0.094

Early care home entrants

1.93

1.46

17% higher for Sutton

73% lower to 414% higher for Sutton

0.831

Late care home entrants

0.91

0.75

20% lower for Sutton

59% lower to 59% higher for Sutton

0.521

Potentially avoidable emergency admissions

Residential care home residents

0.39

0.44

7% lower for Sutton

60% lower to 117% higher for Sutton

0.859

Nursing care home residents

0.54

0.26

122% higher for Sutton

19% to 327% higher for Sutton

0.012

Early care home entrants

1.24

0.46

238% higher for Sutton

42% lower to 664% higher for Sutton

0.193

Late care home entrants

0.47

0.36

28% higher for Sutton

53% lower to 258% higher for Sutton

0.628

A&E attendances

Residential care home residents

1.31

1.83

34% lower for Sutton

64% lower to 22% higher for Sutton

0.184

Nursing care home residents

1.21

0.88

29% higher for Sutton

10% lower to 87% higher for Sutton

0.162

Early care home entrants

2.21

1.59

26% lower for Sutton

81% lower to 182% higher for Sutton

0.660

Late care home entrants

1.28

1.46

70% lower for Sutton

88% to 24% lower for Sutton

0.011

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