Results

After matching, the matched comparison group was similar to the Principia residents across the range of individual and care home characteristics considered. Full information is available in the technical appendix, but for example Principia residents were aged 85.9 years on average, compared with 86.6 years for the matched comparison group. The two groups also had a similar profile of health conditions (see Figure 2). For example, 53% of both Principia and matched comparison residents were recorded as having dementia, while mobility problems were noted for 25% of the Principia residents and 21% of the matched group.

Figure 3 shows trends in hospital utilisation. The left-hand side of each chart shows that the Principia and matched comparison residents experienced similar rates of hospital activity before moving into care homes. This is to be expected due to the matching process. However, some differences still existed for elective admissions and outpatient attendances. The right-hand side shows that, following moving to the care home, the Principia residents appeared to use less hospital care than the matched comparison group for certain types of hospital activity. The regression modelling aimed to quantify how different these patterns were, when adjusting for the residual differences between the two groups in prior hospital use, as well as other baseline characteristics.

After moving to a care home, Principia residents experienced 0.74 A&E attendances each year on average, compared with 1.02 for the matched comparison residents. After regression adjustment, Principia residents attended A&E departments 29% less often than the matched comparison group. The 95% confidence interval suggested a relative difference in the range 11% to 43% (see Table 1).

Therefore, notwithstanding statistical uncertainty, it seemed that the Principia group experienced fewer A&E attendances than the matched comparison group.

Figure 2: Percentage of Principia and matched comparison residents with certain health conditions

Figure 3: Number of hospital contacts per quarter for the Principia and matched comparison residents

Table 1: Hospital utilisation among Principia and matched comparison residents

Crude rates Principia residents (number per person per year)

Crude rates matched comparison residents (number per person per year)

Relative difference from matched comparison group (adjusted rate ratio)

95% confidence interval

p-value

A&E attendances

0.74

1.02

29% lower

11% to 43% lower

0.002

Emergency hospital admissions

0.64

0.78

23% lower

3% to 39% lower

0.024

Potentially avoidable emergency hospital admissions

0.22

0.30

28% lower

0% (no difference) to 49% lower

0.052

Elective hospital admissions

0.11

0.13

29% higher

36% lower to 163% higher

0.445

Outpatient appointments

1.99

1.85

11% higher

12% lower to 40% higher

0.372

Note: this table compares hospital utilisation in the period following moving to a care home. It is based on an average length of stay of 211 days (standard deviation 178 days) among the Principia residents, and 201 days (standard deviation 177 days) for the matched comparison group. For this Table and Table 2, we excluded residents who remained in a care home for under one month, and thus studied 568 Principia residents and 565 matched comparison residents. The adjusted rate ratios were obtained by applying regression models to the matched data. Note that, following adjustment, the Principia group experienced more elective admissions than the matched comparison residents, even though the unadjusted rate was lower. Since the confidence interval was very wide, our analysis for elective admissions was inconclusive.

The Principia group experienced an average of 0.64 emergency admissions per person for each year in the care home, compared with 0.78 for matched comparison residents. After adjustment, Principia residents experienced 23% fewer emergency admissions than the matched comparison group. The 95% confidence interval spanned 3% to 39% so, again, it seemed that there were fewer emergency admissions for Principia residents than the matched comparison group.

Principia residents experienced 0.22 potentially avoidable admissions per person per year, compared with 0.30 for matched comparison residents. After adjustment, there were 28% fewer potentially avoidable admissions among the Principia group. This is, proportionately, a greater change than detected for all emergency admissions (28% compared to 23%), but greater uncertainty existed in the figures for potentially avoidable admissions. For these, the 95% confidence interval spanned 0% (no difference) to 49% fewer admissions. As a result, it was not possible to be confident that the Principia group experienced fewer potentially avoidable admissions than the matched comparison residents.

There was no evidence for a difference in elective admissions and outpatient attendances. On average, the Principia residents spent 3.2% of nights as a hospital inpatient (see Table 2), compared with 4.1% for the matched comparison group. Although Principia residents had 14% lower odds of being an inpatient on any given day, there was substantial uncertainty, with a very wide confidence interval that included the possibility of there being no difference or Principia residents having higher odds. Therefore, it is not possible to conclude that the two groups differed in terms of nights spent in hospital. Also, during the period examined, around one-third of each group of residents died. Among Principia residents, 81.5% of deaths occurred outside of hospital, compared with 83.5% for the matched comparison group. However, after adjustment, Principia residents had 7% greater odds of dying outside of hospital than the matched comparison group, but the confidence interval was very wide and again the analysis was inconclusive.

Table 2: The percentage of nights and deaths experienced in hospital

Crude rates Principia residents (number per person per year)

Crude rates matched comparison residents (number per person per year)

Relative difference from matched comparison group (adjusted odds ratio)

95% confidence interval

p-value

Percentage of nights during which the person was an inpatient at hospital

3.2

4.1

14% lower

43% lower to 29% higher

0.469

Percentage of deaths that occurred outside of hospital

81.5

83.5

7% higher

47% lower to 115% higher

0.851

Note: The adjusted odds ratios were obtained by applying regression models to the matched data. Following adjustment, the Principia group was more likely to die outside of hospital than the matched comparison group, even though a smaller percentage of them died outside of hospital. Our analysis for both metrics was inconclusive, due to the wide confidence intervals.


*** A confidence interval shows some of the uncertainty in the results. Although our best estimate is that the Principia residents attended A&E departments 29% less often than the matched comparison group, the actual difference might lie in the interval from 11% to 43%. There is only a very small (5%) probability that actual difference was higher than 3% or lower than 39%.

Previous Next