Data

The diagnosis and management of COPD in the UK is performed mainly by GPs in the primary care setting; however, the occurrence of acute exacerbations often necessitates hospital treatment. For this reason, data from both the primary and secondary care settings were extracted from the Clinical Practice Research Datalink (CPRD) linked to Hospital Episode Statistics (HES). In 2015, the CPRD covered ~8.5% of the UK population, including practices in England, Northern Ireland, Scotland, and Wales, with 13.1 million research quality acceptable patient records included in the database, known to be broadly representative of the demographic breakdown of the UK population.8 For this study, only the subset of patients in CPRD who could be linked to HES (~58% of the practices) was used. HES contains information on admissions to National Health Service hospitals in England, including records from all admitted patients in acute hospitals, primary care trusts, and mental health trusts. Study protocol approval was given by the Independent Scientific Advisory Committee of the Medicines and Healthcare products Regulatory Agency Database Research (protocol number 15_006R). The data used in this study were non-identifiable, therefore patients’ informed consent was not required as part of the protocol approval process.