Comparative Persistence of Methotrexate and Tumor Necrosis Factor Inhibitors in Rheumatoid Arthritis, Psoriatic Arthritis, and Ankylosing Spondylitis

Objective. The role of methotrexate (MTX) for the treatment of spondyloarthritis (SpA) remains uncertain. Aims were to compare MTX and tumor necrosis factor inhibitor (TNFi) persistence in spondyloarthritis versus rheumatoid arthritis (RA) and to determine whether concomitant conventional synthetic disease-modifying antirheumatic drug (csDMARD) use is associated with improved TNFi persistence in SpA. Methods. This retrospective cohort study using Optum's deidentified Clinformatics Data Mart Database 2000-2014 identified patients with RA, psoriatic arthritis (PsA), and ankylosing spondylitis (AS) without prior biologic use who were initiating MTX or a TNFi. Cox proportional hazards models compared time to medication discontinuation over the next 2 years between patients with RA, PsA, or AS, adjusting for potential confounders. In similar analyses stratified by disease, Cox models were used to assess whether concomitant use of csDMARD was associated with TNFi persistence. Results. We identified 31,527 MTX initiators (26,708 RA, 2939 PsA, 1880 AS) and 34,651 TNFi initiators (24,134 RA, 6705 PsA, 3812 AS). MTX was discontinued sooner in patients with PsA [adjusted HR (aHR) 1.10, 95% CI 1.04-1.16] and AS (aHR 1.23, 1.16-1.31) versus RA, while TNFi were discontinued at similar rates in RA and AS and discontinued later in PsA (aHR 0.93, 0.89-0.97). Concomitant use of MTX (compared to no csDMARD) was associated with lower rates of TNFi discontinuation in RA (aHR 0.85, 0.80-0.89), PsA (aHR 0.81, 0.74-0.89), and AS (aHR 0.79, 0.67-0.93). Conclusion. MTX discontinuation occurs sooner in patients with PsA and AS versus RA. Concomitant use of MTX with a TNFi, however, is associated with improved TNFi persistence in all 3 diseases.