[Prevalence of psoriatic arthritis in a population of patients with psoriasis].

Psoriatic arthritis (PsA) is a chronic inflammatory rheumatic disease characterized by arthritis associated with psoriasis.The aim of the study was to determine the prevalence of psoriatic arthritis in a population of patients with psoriasis. According to literature data, its prevalence varies between 1% and 7%, or only exceptionally more.Seventy-two adult patients with psoriasis were examined. Patients came from the north-west part of Croatia, from different towns with the overall population of more than 150,000, thus making a representative epidemiological sample. Some patients were treated by a dermatologist, whereas others were admitted to rheumatology departments for the problems with locomotor system and were diagnosed as psoriatics. All patients were examined, and their data were processed.Statistical analysis showed the two sexes to be equally involved by psoriasis. In most cases psoriasis preceded arthritis. All arthritis patients had their fingernails affected with psoriasis. In the population of patients with psoriasis, the prevalence of arthritis was higher in men (60%) than in women (40%). Arthritis often occurred (37.5%) in patients with psoriasis localized in the inguinal and/or perianal region with toenail involvement, as compared to 8.9% of patients with arthritis without concurrent psoriasis involvement.The prevalence of arthritis in psoriasis patients was 15.3%.