Trends in psoriatic arthritis epidemiology in Poland.

Psoriatic arthritis (PsA) is a heterogeneous inflammatory arthritis, usually seronegative and associated with psoriasis (Ps). The prevalence and incidence of psoriatic arthritis show strong ethnic and geographic variations. The aim of the study was to assess the epidemiological trends in psoriatic arthritis in Poland. The National Health Fund (NHF) database for the period 2008-2018 was analyzed. PsA was defined as ICD-10 codes L40.5, M07, M07.0, M07.1, M07.2 and M07.3, while psoriasis as ICD-10 codes L40 and L40.X (L40.0 to L40.9). A steady increase in the number of PsA patients (from 16,790 to 32,644) and in PsA recorded prevalence (from 38.47 per 100,000 in 2008 to 73.11 per 100,000 in 2018) was observed between 2008 and 2018. The PsA/Ps ratio increased to a similar extent (from 8.3 to 17.5%). The percentage of PsA patients receiving rehabilitation services remained constant throughout the observation period (mean: 17.35%; range 16.7-18.9%). The study showed a steady and continuous increase in PsA recorded prevalence. A simultaneous increase in the PsA/Ps ratio suggests that the main reason for the observed trend is greater disease detection .