Psoriatic arthritis risk in psoriasis patients prescribed acitretin versus disease-modifying antirheumatic drugs: a nationwide cohort study

Objectives: To compare the risk of PsA in psoriasis (PsO) patients treated with acitretin vs DMARDs. Methods: This retrospective study used Taiwan's National Health Insurance Research Database from 1997 to 2013. Adult PsO patients without PsA prescribed acitretin or DMARDs for ≥30 days within a year were assigned to the acitretin cohort or DMARDs cohort, respectively. Patients in the acitretin cohort prescribed DMARDs for >7 days, or in the DMARDs cohort prescribed acitretin for >7 days, were excluded. Cumulative incidence of PsA were determined within both cohorts using the Kaplan-Meier method. The hazard ratio (HR) comparing acitretin to DMARDs was calculated with Cox regression models, adjusting for demographic and clinical covariates including the use of NSAIDs and comorbidities. Results: The study included 1948 patients in each cohort. The 5-year cumulative incidence of PsA in the acitretin cohort was lower than that in the reference cohort (7.52% vs 9.93%; P = 0.005), with a more pronounced difference in the subpopulation receiving NSAIDs treatment. However, in subpopulations without NSAIDs treatment, the 5-year cumulative incidence of PsA in the acitretin cohort was comparable to the DMARDs cohort (5.26% vs 6.98%; P = 0.106). Acitretin was not associated with PsA development in PsO (HR 0.83, 95% confidence interval 0.65-1.05). This risk remained consistent regardless of adjustments for NSAID treatment and comorbidities. Other independent risk factors for PsA included female and NSAIDs treatment. Conclusion: Compared with DMARDs, acitretin was not associated with increased PsA risk in PsO patients.