Abstract
BACKGROUND: The burden of psoriasis across many world regions is high and there is a recognized need to better understand the epidemiology of this common skin disorder. OBJECTIVES: To examine changes in the prevalence and incidence of psoriasis, and mortality rates over a 15-year period. METHODS: Cohort study involving analysis of longitudinal electronic health records between 1999 and 2013 using the U.K. Clinical Practice Research Datalink (CPRD). RESULTS: The prevalence of psoriasis increased steadily from 2·3% (2297 cases per 100 000) in 1999 to 2·8% (2815 per 100 000) in 2013, which does not appear to be attributable to changes in incidence rates. We observed peaks in age bands characteristic of early-onset (type I) and late-onset (type II) psoriasis, and changes in incidence and prevalence rates with increasing latitude in the U.K. All-cause mortality rates for the general population and for patients with psoriasis have decreased over the last 15 years. However, the risk of all-cause mortality for patients with psoriasis remains elevated compared with people without psoriasis (hazard ratio 1·21; 95% confidence interval 1·13-1·3) and we found no significant change in this relative excess mortality gap over time. CONCLUSIONS: We found an increasing population living longer with psoriasis in the U.K., which has important implications for healthcare service delivery and for resource allocation. Importantly, early mortality in patients with psoriasis remains elevated compared with the general population and we found no evidence of change in this premature mortality gap.