Iguratimod versus salazosulfapyridine in rheumatoid arthritis patients with an inadequate response to methotrexate: Adjusted with propensity score matching

ABSTRACT Objectives Methotrexate (MTX) is recommended as a first-line conventional synthetic disease-modifying antirheumatic drug (csDMARD) for treating rheumatoid arthritis (RA). This retrospective study sought to identify an add-on csDMARD treatment strategy for RA patients with MTX-inadequate response (IR). Methods We collected the cases of RA patients treated with salazosulfapyridine (SASP) or iguratimod (IGU) as the additional csDMARD for MTX-IR during a 24-month follow-up. We performed propensity score matching to evaluate the retention rate, clinical efficacy, and safety profile (n = 54, each group). Results The retention rates at 24 months were 38.5% (MTX+SASP group) and 67.8% (MTX+IGU group). At 3 and 6 months, the MTX+IGU group’s 28 joint-disease activity score (DAS28) was significantly decreased versus the MTX+SASP group, and at 3 months the MTX+IGU group’s good-responder percentage (22.9%) was significantly higher versus the MTX+SASP group’s good-responder percentage (10.7%). Conversely, compared to the MTX+SASP group, the MTX+IGU group showed a greater reduction in the estimated glomerular filtration rate from baseline during follow-up. Conclusions IGU is a useful add-on csDMARD for RA patients with MTX-IR; its high retention rate and good clinical response make it a useful combination therapy for controlling RA disease activity. However, the renal function should be monitored during follow-up.