Prevalence of Psoriatic Arthritis in a Large Cohort of Brazilian Patients with Psoriasis

Objective. To determine the prevalence of psoriatic arthritis (PsA) in a large cohort of Brazilian patients with psoriasis (PsO) being seen at dermatology centers. Methods. A multicenter study was conducted in 4 university dermatology clinics. In each center, consecutive patients with confirmed diagnoses of PsO were evaluated by a rheumatologist. Individuals were classified as having PsA according to the ClASsification criteria for Psoriatic ARthritis (CASPAR). Laboratory tests and radiographs were performed, as needed, based on the clinical judgment of the rheumatologist. Results. A total of 524 patients with PsO were evaluated. The mean age was 48.5 +/- 14.5 years, 50% were women, and the mean PsO duration was 15.4 +/- 11.7 years. A diagnosis of PsA was documented in 175 patients (33%), of whom 49% were newly identified by the rheumatologist. Most individuals with PsA (72%) had peripheral involvement, 11% had isolated axial involvement, and 17% had both peripheral and axial involvement. Dactylitis occurred in 20% and clinical enthesitis in 30% of the patients. Laboratory and/or radiograph tests were necessary for a definitive diagnosis of PsA in 42 of 175 individuals (24%). Conclusion. In our study, one-third of Brazilian patients with PsO, followed in dermatology settings, were diagnosed with PsA by a rheumatologist. Almost half of subjects with PsA had no previous diagnosis. A collaboration between dermatologists and rheumatologists is greatly needed to establish earlier PsA diagnoses and adequate multidisciplinary management.