One of the most important long-term side effects of therapy for rheumatoid arthritis (RA) is the elevation of liver function tests, with earlier studies reporting an elevation of more than 1× the upper limit of normal (>1 × ULN). The current study expands the literature by comparing the trends of transaminase changes caused by conventional and biologic disease-modifying antirheumatic drugs (DMARDs).
The drug categories examined were methotrexate (MTX) and all other nonbiologic DMARDs. Where RA patients exhibited inadequate response to conventional DMARDs (cDMARDs), we added biologic DMARDs (bDMARDs) to the treatment. We compared the trend of changes in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the patients receiving MTX with the trend observed in the patients whose treatment encompassed both bDMARDs and MTX. The comparison was conducted using random intercept models, which are a type of linear mixed effects model.
This work involved 512 RA patients (MTX: 450, MTX + infliximab [INF]: 26, MTX + etanercept [ETA]: 36), whose ALT and/or AST levels were measured in 1,786 visits (MTX: 1,543, MTX + INF: 107, MTX + ETA: 136). ALT and/or AST elevations greater than 1 × ULN were observed in 344 (19.3%) visits (MTX: 295 [19.1%], MTX + INF/ETA: 49 [20.2%]). In this study, the trends of ALT and AST changes increased when receiving MTX, while the INF/ETA addition decreased these trends. The random intercept models indicated that changes in the mean ALT levels were significantly different over the time for MTX and MTX + INF/ETA groups (β [SE] =−0.190 [0.093], P= 0.040) but changes in the mean AST levels were nonsignificantly different over the time for such groups (β [SE] =−0.099 [0.064], P=0.120).