Prevalence of psoriatic arthritis in patients with psoriasis: A systematic review and meta-analysis of observational and clinical studies.

BACKGROUND: Wide-ranging prevalence estimates of psoriatic arthritis (PsA) in patients with psoriasis have been reported. OBJECTIVES: To assess the prevalence and incidence of PsA in patients with psoriasis. METHODS: Two authors independently searched 3 databases for studies reporting on the prevalence or incidence of PsA in patients with psoriasis. A proportion meta-analysis was performed to calculate the pooled proportion estimates of PsA in patients with psoriasis. RESULTS: A total of 266 studies examining 976,408 patients with psoriasis were included. Overall, the pooled proportion (95% confidence interval [CI]) of PsA among patients with psoriasis was 19.7% (95% CI, 18.5%-20.9%). In children and adolescents (<18 years of age), the pooled prevalence was 3.3% (95% CI, 2.1%-4.9%). The PsA prevalence was 22.7% (95% CI, 20.6%-25.0%) in European patients with psoriasis, 21.5% (95% CI, 15.4%-28.2%) in South American patients with psoriasis, 19.5% (95% CI, 17.1%-22.1%) in North American patients with psoriasis, 15.5% (95% CI, 0.009%-51.5%) in African patients with psoriasis, and 14.0% (95% CI, 95% CI, 11.7%-16.3%) in Asian patients with psoriasis. The prevalence of PsA was 23.8% (95% CI, 20.1%-27.6%) in studies in which the Classification Criteria for Psoriatic Arthritis were applied. The incidence of PsA among patients with psoriasis ranged from 0.27 to 2.7 per 100 person-years. LIMITATIONS: Between-study heterogeneity may have affected the estimates. CONCLUSIONS: We found that 1 in 4 patients with psoriasis have PsA. With the growing recognition of the Classification Criteria for Psoriatic Arthritis, more homogenous and comparable prevalence estimates are expected to be reported.