Prevalence of psoriasis and psoriatic arthritis in Germany - analysis of claims data

Background and Objectives Few studies are available on the epidemiology of psoriasis and psoriatic arthritis in Germany. The aim of this study was to estimate this prevalence based on different case definitions.Methods Statutory health insurance (SHI) data were examined (2017 to 2019). Prevalence was analyzed and validated using three different case definitions: (1) At least one inpatient or outpatient diagnosis within one year, (2) additionally at least two outpatient diagnoses within one year, (3) additionally within three years.Results The administrative prevalence of psoriasis including psoriatic arthritis ranged from 1.90% to 2.51%. For all case definitions, the prevalence increased with age, decreasing from the age of 70 with psoriasis and from the age of 65 with psoriatic arthritis. Males were more likely to be affected at an older age (p <0.0001), while in the under-20 age group, more girls were affected (p = 0.04).Conclusions Psoriasis is a common skin disease in Germany. The internal diagnoses validation showed that in future studies with claims data, the narrow and broad criteria should be used to identify patients with psoriasis, depending on the research question.