Table 7

Impact on length of stay per emergency admission and emergency readmission rates

CoefficientLower 95% CIUpper 95% CIP value
Result of difference-in-differences analysis showing the change in length of stay in days per emergency COPD admission in Knowsley following the intervention relative to the control group, 2005–2016
 Spline 10.06−0.480.60.828
 Spline 2−0.75−1.550.050.065
 Population aged 50+ years (%)0.1100.210.046
 Population female (%)0.03−0.310.360.868
 Working age population unemployed (%)*−1.11−3.671.450.395
 Treatment (Knowsley=1; control=0)0.26−1.922.450.813
 Period (postintervention=1; preintervention=0)−1.65−4.250.940.211
 DiD estimator (treatment*period)−0.95−3.982.080.538
Result of difference-in-differences analysis showing the change in COPD emergency readmissions per 100 000 population in Knowsley following the intervention relative to the control group, 2005–2016
 Spline 1−5.77−7.72−3.81<0.001
 Spline 23.730.736.740.015
 Population aged 50+ years (%)0.21−0.310.730.43
 Population female (%)1.01−0.552.580.204
 Working age population unemployed (%)*25.4413.6637.22<0.001
 Treatment (Knowsley=1; control=0)−1.6−11.468.250.749
 Period (postintervention=1; preintervention=0)4.21−4.9413.360.367
 DiD estimator (treatment*period)3.39−7.3714.140.537
  • Model includes random intercept for LSOA.

  • Model based on 71 Knowsley and 268 control LSOAs, and 4068 observations.

  • Model based on 69 Knowsley and 266 control LSOAs, and 4020 observations.

  • LSOAs which had zero COPD emergency admissions for any year of the study period were removed when analysing the emergency readmission rate outcome.

  • LSOAs which had zero COPD emergency admissions for any year of the study period were removed when analysing the length of stay outcome, since length of stay was not applicable when zero admissions occurred.

  • *Variable entered into model in units of 10% points.

  • COPD, chronic obstructive pulmonary disease; DiD, difference-in-differences; LSOA, lower-layer super output area.