Global epidemiology of psoriatic arthritis.

Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disease that develops in a substantial proportion of patients with psoriasis (PsO). Understanding its epidemiology is essential for improving early recognition, risk stratification, and preventive strategies. This review summarizes current evidence on the global prevalence and incidence of PsA in both the general population and among individuals with PsO. Population-based studies estimate PsA prevalence at approximately 0.1-0.2%, with considerable geographic variability. Among patients with PsO, approximately 20% develop PsA, although this proportion varies according to age, disease severity, classification criteria, and region. Incidence rates in the general population range from 3 to 41 per 100,000 person-years, with evidence of increasing prevalence over time in several countries, likely reflecting improved recognition and diagnostic practices. Risk factors for PsA development include severe PsO, nail involvement, obesity, and the presence of musculoskeletal symptoms, particularly inflammatory arthralgia. Emerging data suggest that advanced systemic therapies for PsO may influence future PsA incidence, although prospective evidence is still needed. Significant heterogeneity in epidemiological estimates is driven by methodological differences, diagnostic criteria, healthcare systems, and underdiagnosis. A better understanding of epidemiological trends and transition phases from PsO to PsA may support earlier identification and optimized multidisciplinary management strategies.