The epidemiology of psoriasis in an Italian area: population-based analysis of administrative data

BACKGROUND: Data on the epidemiology of psoriasis are limited. The objective of this study was to estimate the prevalence and the incidence rate of psoriasis in a reproducible and efficient population-based assessment in a Northeastern Italian area around the city of Udine. METHODS: A retrospective population-based analysis was conducted linking at the individual patient level, through a unique encrypted identifier, four electronic administrative health databases, with full coverage of the residing population: the hospital discharge database, the ambulatory care database, the pharmaceutical prescriptions database, and the database of exemptions from medical charges. Incident and prevalent cases of psoriasis were identified through predefined algorithms. RESULTS: The estimated prevalence of psoriasis in the study area was 1.84%, while incidence rate was 0.96/1000 person-years; 13.6% of prevalent cases had arthritis. Prevalence turned out to increase with age and was higher in males. Arthritis was more common among females. Biological medications were prescribed to 2% of patients in 2015. CONCLUSIONS: Our estimates of incidence and prevalence of psoriasis and description of patients characteristics in the North-East of Italy add knowledge to the existing body of scientific data on the epidemiology of this disease at the international level and provide useful information for health planners at the local level.