Prevalence and Factors Associated with Psoriatic Arthritis among Psoriasis Patients on Follow-up at the Dermatology and Rheumatology Units, Kenyatta National Hospital, Kenya

Abstract

Background: Psoriatic arthritis (PsA) is a serious and potentially debilitating condition that frequently occurs in individuals with psoriasis. The burden of PsA ranges between 6 – 42 percent globally and occurs in approximately 30% of patients with psoriasis. However, the burden of PsA has not been fully investigated within the local context. Purpose of the study: To determine the prevalence and factors associated with psoriatic arthritis among psoriasis patients on follow-up at the Dermatology and Rheumatology units, Kenyatta National Hospital. Methodology: This was a cross-sectional study conducted at Kenyatta National Hospital. A consecutive sampling technique was used to sample 80 patients diagnosed with psoriasis. A structured questionnaire was used to collect data. The CASPAR criteria were used to screen for PsA. The prevalence of PsA was obtained as a proportion of patients with PsA over the total sample size and expressed as a percentage. Bivariate and multivariable analyses were done to investigate factors associated with PsA using binary logistic regression. A STATA version 16 was used to analyse the data. Results: The Majority of the patients were male (65%), 47.5% were aged between 31 and 49 years, with the youngest being four years and the oldest being 75 years. Further, 52.5% had psoriasis for more than 48 months, and 33.8% had a family history of psoriasis. The average PASI score was 11.5 (SD=8.9). The common type of psoriasis was plaque (70%), and the common site of psoriasis included the extremities (78.8%). The prevalence of psoriasis arthritis was 23(28.8%) with a 95%CI: 19.4% to 40.2%. The common psoriatic arthritis subtypes included polyarticular arthritis (39.1%), spondylarthritis (26.1%), and oligoarticular arthritis (21.7%). The multivariable analysis revealed that significant factors associated with Psoriatic Arthritis include gender (females, aOR = 10.11, 95% CI: 1.12, 91.61, p = 0.040), history of smoking (aOR = 21.37, 95% CI: 2.45, 186.71, p = 0.006), nail involvement (aOR = 5.44, 95% CI: 2.69, 42.1, p = 0.006), onycholysis morphology (aOR = 11.39, 95% CI: 1.42, 91.50, p = 0.022), Oil drops (aOR = 12.11, 95% CI: 1.44, 34.12, p = 0.034), and the PASI score (aOR = 2.11, 95% CI: 1.34, 6.11, p < 0.001). Conclusion and recommendations: Psoriatic arthritis (PsA) burden is high, with polyarticular arthritis being the most common subtype. Female gender, smoking history, nail involvement, onycholysis morphology, Oil drops, and a higher PASI score are key contributors to the likelihood of developing PsA. Early monitoring for these factors is recommended.