Factors predicting addition of disease-modifying antirheumatic drugs after initial methotrexate monotherapy in patients with rheumatoid arthritis

We investigated factors predicting the addition of disease-modifying antirheumatic drugs (DMARDs) after an initial methotrexate (MTX) monotherapy in rheumatoid arthritis (RA) patients to support an early decision on the DMARDs addition.

This retrospective cohort study included 311 patients who were diagnosed with RA and started on MTX monotherapy at Showa University Hospital, Japan. The outcome was addition of DMARDs after an initial MTX monotherapy at 6 months. Baseline patient characteristics were compared between the DMARDs addition and MTX monotherapy continuation groups, and significant independent predictive factors for the addition of DMARDs were selected using multivariate analysis.

The median age of patients was 62 years (range 24-90), 170 patients (73%) were women, the median swollen 28-joint count (SJC28) was 3 (0-28), and the median tender 28-joint count (TJC28) was 5 (0-28). DMARDs were added in 65 (27.9%) patients. In the univariate analysis, higher TJC28 and SJC28, concomitant use of nonsteroidal anti-inflammatory drugs, and intra-articular glucocorticoid (GC) injection history were significantly associated with the DMARDs addition. In the multivariate analysis, by adding covariates to the variables identified in the univariate analysis, SJC28 (odds ratio [OR] 1.390 per 5 joints increase; 95% confidence interval [CI], 1.036-1.866) and intra-articular GC injection history (OR 3.678; 95% CI, 1.170-11.557) were independent predictors of DMARDs addition.

A higher SJC28 and intra-articular GC injection history may be useful predictors of DMARDs addition after the initial MTX monotherapy. We expect that using these predictors will enable an earlier shift to a more aggressive treatment. Key Points ・We performed a retrospective cohort study with the addition of DMARDs as the outcome in patients with RA who were started on MTX monotherapy. ・A higher SJC28 (OR 1.390; 95% CI, 1.036-1.866) and an intra-articular GC injection history (OR 3.678; 95% CI, 1.170-11.557) may be useful predictors for the addition of DMARDs of initiating MTX monotherapy at 6 months. ・The use of such indicators may support an early decision on the addition of DMARDs after the initial MTX monotherapy.