OBJECTIVES: Although not indicated for psoriatic arthritis (PsA), methotrexate (MTX) is commonly prescribed as first-line treatment in this population. While inexpensive, the efficacy, treatment burden, and effectiveness of MTX over time in PsA patients is still unclear. Therefore, the objective of this study was to evaluate the costs and benefits of first-line MTX in MTX- and bio-naïve PsA patients over time.

METHODS: We performed a decision tree analysis, using clinical and utility inputs for 4, 8, 12, 16, 24, 36, and 48 weeks of MTX use from the MTX arm of Amgen’s randomized controlled trial assessing etanercept and MTX as monotherapy or in combination for PsA (SEAM-PsA). We estimated cost inputs from Medicare Fee Schedule, AnalySource, and published studies. For year 1, we calculated cumulative costs and quality-adjusted life years (QALYs) from observed data in SEAM-PsA. We modeled costs and QALYs for years 2-5 post-MTX use using data from SEAM-PsA and observational studies. We performed a probabilistic sensitivity analysis (PSA) to test the robustness of the results.

RESULTS: Mean utility increased in the first year of MTX use, then generally decreased over time, decreasing below baseline by year 3. Costs and cost/QALY increased after the first year of MTX use, and generally continued to increase over time with MTX use. We present our results in an interactive ShinyApp tool.

CONCLUSIONS: MTX may have more costs compared to benefits in new PsA patients naïve to treatment, especially over time. Physicians and patients should consider the long-term benefits and costs of MTX when evaluating PsA treatment options.