Cost-effectiveness of early versus delayed disease-modifying antirheumatic drugs for psoriatic arthritis

Background Disease-modifying antirheumatic drugs (DMARDs) are standard first-line therapy for psoriatic arthritis (PsA). Observational studies suggest earlier initiation is associated with superior minimal disease activity (MDA) attainment, yet the economic and health implications of treatment timing remain uncertain. This cost-utility analysis evaluated the cost-effectiveness of early versus delayed DMARD initiation in DMARD-naive adults with PsA from a U.S. payer perspective. Methods We built a cohort state-transition (Markov) model (monthly cycles, 15-year horizon) from published data (2000–2025). Patients initiated a DMARD under two strategies: early (≤1 year post-diagnosis) and delayed initiation (>1 year). Patients remained in the pre-treatment state for six months prior to response assignment, then transitioned among complete response (sustained MDA), partial response (non-sustained MDA), non-response, no treatment, and death. Primary outcomes included the incremental cost-effectiveness ratio (ICER) and incremental net monetary benefit (INMB). Uncertainty intervals (UIs) were derived from probabilistic sensitivity analyses. Findings Early DMARD initiation provided an additional 0.56 (95% UI, 0.32–0.83) QALYs at an incremental cost of –US$43,902.94 (95% UI, –US$147,096.29 to US$61,615.86) per patient relative to delayed initiation, yielding a favourable ICER (–US$78,398.11/QALY). At a willingness-to-pay threshold of US$50,000/QALY, mean INMB was US$71,902.94 (95% UI, –US$36,663.51 to US$176,658.91), with early initiation preferred in 90.6% of simulations. Interpretation Early DMARD initiation was associated with improved long-term health outcomes at reduced costs, suggesting timely DMARD initiation may represent a high-value strategy. Given the observational basis of the key treatment-timing input, findings support disease-duration stratified analyses of existing phase III trials and further characterization of access delays. Funding None.