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

Abstract

Psoriatic arthritis (PsA) is a serious and potentially debilitating condition that frequently occurs in approximately 30% of 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. The main study purpose was to determine the prevalence and clinical factors associated with psoriatic arthritis among psoriasis patients on follow-up at the Dermatology and Rheumatology units, Kenyatta National Hospital, Kenya. This was a cross-sectional study conducted at Kenyatta National Hospital over a period of five months. 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 analyze the data. The findings indicated that 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 with a first degree relative. 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 psoriatic 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). The study concluded that 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.