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.