Alinaghi F, et al. - Researchers evaluated the prevalence and incidence of psoriatic arthritis (PsA) in patients with psoriasis. They performed a proportion meta-analysis to calculate the pooled proportion estimates of PsA in patients with psoriasis. PsA was found in one in five patients with psoriasis. In European psoriasis patients, the PsA prevalence was 22.7%, it was 21.5% in South American, 19.5% in North American, 15.5% in African, and 14.0% in Asian.