Table 1

Description of matching variables

Matching variableDetails
Age and gender profile of the populationAnnual data on the size of the female population and the population aged 50+ years per lower super output area (LSOA) were derived from midyear population estimates provided by the Office for National Statistics (ONS).
Unemployment rateAnnual unemployment rates were calculated using claimant data provided by the ONS. Unemployment was measured as the proportion of people aged 16–64 years claiming Jobseeker’s Allowance or Universal Credit principally for the reason of being unemployed.
Chronic obstructive pulmonary disease (COPD) emergency admission rateEmergency admissions for COPD were defined using ICD-10 codes: J40–J44. Annual COPD emergency admission rates per 100 000 population were calculated using Hospital Episode Statistics, with population data obtained from the ONS. Continuous inpatient spells were used to calculate emergency admissions per calendar year.
Indices of Multiple DeprivationIndex of Multiple Deprivation 2015 data were provided by the Department for Communities and Local Government.
Quality and outcomes framework (QOF) indicatorsQOF indicator data for the prevalence of COPD and smoking, and the percentage of patients with COPD receiving inhaled treatment whose inhaler technique had been checked within the previous 15 months were included in the propensity score model. Weighted averages of QOF indicators per LSOA were calculated using data provided by NHS Digital on the number of patients registered per general practice per LSOA.
Numbers of general practitioners (GPs) per capita serving the populationWeighted averages of the number of full-time employed GPs per 1000 population were calculated using data provided by NHS Digital on the no of GPs and patients registered per general practice per LSOA.
Distance to the nearest general practice and hospitalThe Consumer Data Research Centre provided data per LSOA on the average road network distance to the nearest hospital with an Accident and Emergency department, and the nearest general practice. Road network distances in kilometres were calculated by deriving the fastest route by car to travel from each postcode within an LSOA to the nearest health service.
  • The following variables were included in a propensity score model to match Knowsley to control areas in the time period before the introduction of the intervention (2005–2010).

  • NHS, National Health Service.