Prevalence of undiagnosed psoriatic arthritis among psoriasis patients: Systematic review and meta-analysis

Background: Skin psoriasis precedes the onset of psoriatic arthritis (PsA) in 84% of patients with psoriasis. Dermatologists have an important role to screen psoriasis patients for PsA. The efficiency of PsA screening remains unknown. Objective: We sought to determine the point prevalence of undiagnosed PsA in patients with psoriasis using a systematic search of the literature and meta-analysis. Methods: PubMed, Cochrane, and Embase database searches yielded 394 studies for review. No study aimed to determine the prevalence of undiagnosed PsA in patients with psoriasis. We assumed that the prevalence of newly diagnosed PsA in patients with psoriasis at the time they seek medical care could be a sound estimate of this value. Seven epidemiological studies and 5 studies on PsA screening questionnaires allowed us to clearly identify patients with newly diagnosed PsA and were selected for review. Results: The prevalence of undiagnosed PsA was 15.5% when all studies were considered and 10.1% when only epidemiological studies were considered. Limitations: Data were obtained from studies not designed to address the question at hand. Heterogeneity was high (I-2 = 96.86%), and therefore a random effects model was used. Conclusion: The high prevalence of undiagnosed PsA in patients with psoriasis adds to the recommendation that dermatologists need to screen all patients with psoriasis for PsA.