Six-month flare risk after discontinuing long-term methotrexate treatment in patients having rheumatoid arthritis with low disease activity.

Abstract

We investigated the disease flare rate in patients with rheumatoid arthritis (RA) who achieved low disease activity following long-term methotrexate (MTX) treatment and the factors related to flare. This retrospective longitudinal cohort study included patients with RA and low disease activity who were exposed to MTX for >10years. Disease flare was defined as an increase in Disease Activity Score of 28 joints (DAS28) of >1.2 within 6months of discontinuation of MTX. Logistic regression analysis was performed to identify the factors associated with flare. In total, 97 patients with RA were included in the study. The mean baseline DAS28 was 1.96±0.56. The median cumulative MTX dose was 11.7g; the median duration of exposure to MTX was 19years. Following MTX discontinuation, flare occurred in 43 (44.3%) patients; the median time to flare was 99 (28-168) days. According to univariate logistic regression analysis, C-reactive protein, erythrocyte sedimentation rate (ESR) at discontinuation, the average ESR in the 6months before discontinuation of MTX, a weekly dose of MTX before discontinuation, and use of other conventional synthetic disease-modifying antirheumatic drugs were associated with a higher risk of disease flare. In multivariable analysis, a weekly dose of MTX before discontinuation (odds ratio 1.014; 95% CI 1.014-1.342; P=.031) was significantly associated with flare risk. Among patients with RA who achieved low disease activity with long-term treatment with MTX, more than half remained flare free after MTX discontinuation. A higher MTX dose before discontinuation was associated with a high flare risk.