12 There are data on demographics and diagnoses based on Read codes. Only patients who had not deregistered from the participating GP practices and did not consult a GP for asthma between 1996–1997 and 2000–2001 will be taken into account. Prevalence

We will estimate the annual and lifetime prevalence of asthma,13 based on (a) national Palbociclib Phase 3 health surveys for the: (i) patient’s report of symptoms indicative of asthma (usually wheezing); (ii) patient’s report of doctor-diagnosed asthma and (iii) patient’s report of doctor-diagnosed asthma and doctor-treated asthma; and (b) primary care for GP-diagnosed asthma and GP-treated asthma. We also aim to estimate the prevalence of asthma that is likely to be allergic in origin, on the basis of the patient having anaphylaxis, conjunctivitis, eczema, food allergy, allergic rhinitis and urticaria (see online supplementary appendix 5). Since up to 15% of patients with chronic obstructive pulmonary disease (COPD) may also have asthma, we will also estimate the prevalence of COPD in those with asthma aged 40 years and above (see online supplementary appendix 6).14 Since smoking is the key risk factor for COPD, past and current

smoking status will be queried (see online supplementary appendix 7). The health surveys to be used are the: Health Survey for England (HSE) of 2001, 2004 and 2010; Northern Ireland Health and Social Wellbeing Survey and the Northern Ireland Health Survey of 2001, 2005/2006, 2010/2011 and 2011/2012; Scottish Health Survey (SHeS) of 2003, 2008 and 2010; and the Welsh Health Survey (WHS) of 2003, 2007, 2008, 2010 and 2011. These surveys are of randomly selected samples of people broadly representative of the respective general population. They involve the collection of information on health and utilisation of health services. Survey data will be obtained from the UK Data Service.15 The prevalence estimates from the GP databases will come from WRS in England,

PTI in Scotland, SAIL in Wales and the Quality and Outcomes Framework (QOF) database across the four countries. QOF data are GSK-3 available from 2004. QOF is a fundamental part of the UK General Medical Services contract, whereby general practices are rewarded by incentives for providing quality care to their patients.15 16 QOF data are, however, aggregated numbers; hence, breakdown by age and gender is impossible. Healthcare utilisation in primary care GP and nurse consultations For estimating GP and nurse consultations for asthma, WRS and HSE will be used for England, PTI and SHeS for Scotland and SAIL-GP for Wales. We have not been able to identify any suitable data source for Northern Ireland. Prescriptions Some treatments commonly used for asthma (see online supplementary appendix 4) may be used for the management of other disorders.