Result of difference-in-differences analysis showing the change in COPD emergency admissions per 100 000 population in Knowsley following the intervention relative to the control group, for areas with low income deprivation, 2005–2016
| Coefficient | Lower 95% CI | Upper 95% CI | P value | |
| Treatment (Knowsley=1; control=0) | −15.78 | −65.11 | 33.54 | 0.528 |
| Period (postintervention=1; preintervention=0) | −25.70 | −57.65 | 6.25 | 0.115 |
| DiD estimator (treatment*period) | 29.99 | −9.88 | 69.86 | 0.140 |
Model includes random intercept for LSOA, and fixed effects for per cent of population aged 50+ years, per cent female, per cent unemployed and two spline terms for time (full model results are given in online supplementary file).
Model based on 29 Knowsley and 135 control LSOAs, and 1968 observations.
COPD, chronic obstructive pulmonary disease; DiD, difference-in-differences; LSOA, lower-layer super output area.