Cumulative retention rates of methotrexate therapies. Kaplan-Meier analysis of retention rates of methotrexate. The different panels show (a) the overall drug retention, (b) retention of drug effectiveness, and (c) retention of drug safety for original therapy (grey lines; oMTX) and re-employed therapy (black lines; rMTX). Overall retention rates were similar between the two groups (panel a: P = 0.31, by log-rank test). Likewise, retention because of safety was similar between groups (panel c: P = 0.23). Retention because of effectiveness was better for the rMTX group (panel b: P < 0.01).