Incidence, prevalence and mortality of bullous pemphigoid in England 1998–2017: a population-based cohort study

© 2020 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists. Background: A rising incidence and high mortality were found for bullous pemphigoid (BP) over a decade ago in the UK. Updated estimates of its epidemiology are required to understand the healthcare needs of an ageing population. Objectives: To determine the incidence, prevalence and mortality rates of BP in England from 1998 to 2017. Methods: We conducted a cohort study of longitudinal electronic health records using the Clinical Practice Research Datalink and linked Hospital Episode Statistics. Incidence was calculated per 100 000 person-years and annual point prevalence per 100 000 people. Multivariate analysis was used to determine incidence rate ratios by sociodemographic factors. Mortality was examined in an age-, sex- and practice-matched cohort, using linked Office of National Statistics death records. Hazard ratios (HRs) were stratified by matched set. Results: The incidence was 7·63 [95% confidence interval (CI) 7·35–7·93] per 100 000 person-years and rose with increasing age, particularly for elderly men. The annual increase in incidence was 0·9% (95% CI 0·2–1·7). The prevalence almost doubled over the observation period, reaching 47·99 (95% CI 43·09–53·46) per 100 000 people and 141·24 (95% CI 125·55–158·87) per 100 000 people over the age of 60 years. The risk of all-cause mortality was highest in the 2 years after diagnosis (HR 2·96; 95% CI 2·68–3·26) and remained raised thereafter (HR 1·54; 95% CI 1·36–1·74). Conclusions: We report a modest increase in the incidence rate of BP, but show that the burden of disease in the elderly population is considerable. Mortality is high, particularly in the first 2 years after diagnosis. What is already known about this topic?. Bullous pemphigoid (BP) is a blistering skin disorder which typically affects the elderly. BP poses a high burden on affected patients and has significant healthcare costs. The burden of disease in the UK was estimated over a decade ago and found to have a rising incidence and high mortality. What does this study add?. The incidence of BP in England was 7·63 (95% CI 7·35–7·93) per 100 000 person-years between 1998 and 2017. The burden of BP in the elderly population is substantial and it should not be considered a rare disease in these age groups. The risk of death was almost three times higher in the first 2 years after a diagnosis of BP compared with people without the disease and remained raised thereafter.