Prevalence and risk factors associated with psoriatic arthritis among patients with psoriasis

Psoriatic arthritis is a chronic, autoimmune inflammatory arthritis that occurs with psoriasis and has profound impact on patients' physical and psychological well-being. This study aims to determine the prevalence and risk factors associated with psoriatic arthritis among patients with psoriasis.A single-center, cross-sectional study was conducted over a 12-month period at the Dermatology Clinic, Hospital Pulau Pinang, Malaysia involving all consecutive psoriasis patients. CASPAR (ClASsification of Psoriatic ARthritis) criteria were used to diagnose psoriatic arthritis.A total of 360 patients with psoriasis were recruited, of whom 107 (29.7%) had psoriatic arthritis. Psoriatic arthritis patients had equal gender distribution and the mean age of arthritis onset was 40.7 ± 12.8 years. Psoriasis preceded arthritis in 81.3% of patients (n = 87) with a mean latency interval of 10.5 years. Polyarthropathy was the predominant subtype affecting 46.8% (n = 50) of patients, followed by oligoarthropathy (22.4%, n = 24), axial joint disease (5.6%, n = 6), predominant distal interphalangeal joint disease (2.8%, n = 3), and mixed subtype (22.4%, n = 24). Enthesitis and dactylitis occurred in 12.1% (n = 13) and 20.6% (n = 22) of arthritis patients, respectively, and deformity was present in 37.4% (n = 40). Psoriatic arthritis was significantly associated with being an ever smoker (adjusted odds ratio [aOR] 0.41; 95% confidence interval [CI] 0.18-0.91, p = .029), genital psoriasis (aOR 2.25; 95% CI 1.17-4.33, p = .015), and increased erythrocyte sedimentation rate (ESR) (aOR 1.02; 95% CI 1.01-1.04, p = .005) and C-reactive protein [CRP] (aOR 1.04; 95% CI 1.00-1.08, p = .040).Our study showed a high prevalence of psoriatic arthritis among the psoriasis cohort. Genital involvement, and increased ESR and CRP were associated with psoriatic arthritis among patients with psoriasis.