Table 12

Result of difference-in-differences analysis showing the change in COPD emergency admissions per 100 000 men in Knowsley following the intervention relative to the control group, 2005–2016

CoefficientLower 95% CIUpper 95% CIP value
Treatment (Knowsley=1; control=0)18.50−37.0774.070.513
Period (postintervention=1; preintervention=0)−22.72−62.6317.190.264
DiD estimator (treatment*period)−59.80−107.29−12.320.014
  • 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 98 Knowsley and 392 control LSOAs, and 5880 observations.

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