Approximately 1 in 5 patients with psoriasis have psoriatic arthritis (PsA), with consistent results reported across numerous strata, according to a systematic review and meta-analysis of observational and clinical studies published in the Journal of the American Academy of Dermatology.
The investigators sought to assess the incidence and prevalence of PsA in patients with psoriasis. A total of 266 studies were included in the meta-analysis, in which 976,408 patients with psoriasis were evaluated. Overall, the pooled prevalence of PsA in patients with psoriasis was 19.7% (95% CI, 18.5%-20.9%); in children and adolescents age <18, 3.3% (95% CI, 2.1%-4.9%); and in patients with moderate to severe psoriasis, 24.6% (95% CI, 22.9%-26.4%).
The prevalence of PsA in patients with psoriasis was also assessed based on continent. In 119 studies from Europe, the pooled prevalence of PsA in patients with psoriasis was 22.7% (95% CI, 20.6%-25.0%); in 59 studies from Asia, 14.0% (95% CI, 11.7%-16.3%); in 47 studies from North America, 9.5% (95% CI, 17.1%-22.1%); in 10 studies from South America, 21.5% (95% CI, 15.4%-28.2%); and in 3 studies from Africa, 15.5% (95% CI, 0.009%-51.5%).
Moreover, in studies in which the Classification Criteria for Psoriatic Arthritis (CASPAR) were applied, the pooled prevalence of PsA in patients with psoriasis was 23.8% (95% CI, 20.1%-27.6%). In individuals with psoriasis, the incidence of PsA ranged from 0.27 to 2.7 per 100 person-years.
The investigators noted that between-study heterogeneity may have affected the interpretation of the results and outcomes. They concluded that with the growing recognition of CASPAR, it is anticipated that more homogenous, comparable prevalence estimates will be reported.
Several authors have disclosed funding from pharmaceutical companies. Please see original article for a full list of disclosures.
Alinaghi F, Calov M, Kristensen LE, et al. Prevalence of psoriatic arthritis in patients with psoriasis: a systematic review and meta-analysis of observational and clinical studies [published online June 18, 2018]. J Am Acad Dermatol. doi:10.1016/j.jaad.2018.06.027