Epidemiology of Psoriasis in Germany - Analysis of Secondary Health Insurance Data

Background: In Germany, population-based data on the epidemiology of psoriasis are still rare. This study aims to assess the prevalence of psoriasis in the total population as well as for subgroups relevant to health care. As further epidemiological parameters the severity and regional distribution of psoriasis were analysed. Methods: A secondary analysis of data collected routinely for the members of a nationwide statutory health insurance company was conducted. Prevalences were calculated for a closed cohort of continuously insured persons in 2005. Defined criteria for the existence of psoriasis were at least one diagnoses of psoriasis (ICD-10) relating to ambulatory or hospital treatment or disability. Results: 33 981 of the 1 344 071 continuously insured persons in 2005 were diagnosed with psoriasis, thus the one-year-prevalence in this cohort was 2.53 %. Up to the age of 80 years the prevalence rate was increasing with increasing age and highest for the age groups from 50 to 79 years (range: 3.99-4.18 %). Insured persons up to 20 years had a prevalence of 0.73 %. Regional differences showed up after stratification for broad categories (1 digit) of ZIP codes: Lowest prevalence rates were seen in the south (2.17 %) and highest (2.78 %) in the north and western regions of Germany. Conclusions: If the prevalence rate of 2.5 % assessed in this study is applied to the total resident population, 2 million people are treated because of psoriasis in Germany. Routine data from health insurance companies are a relevant and suitable data source to assess the prevalence of chronic diseases (under medical treatment) in the population.