Seven RCTs (n=2,763, range 29 to 1,004) were included in the review. All trials were judged to be high quality.
Use of combination therapy was associated with significantly higher achievement of clinical remission at one year (RR 1.74, 95% CI 1.54 to 1.98; seven RCTs) and radiologically confirmed non-progression of disease (RR 1.30, 95% CI 1.01 to 1.68, I2=94.7%; four RCTs, n=2,566).
Withdrawals due to lack of efficacy were higher in the methotrexate monotherapy group (range 3.2% to 36%) than the combination therapy groups (zero to 17%).
There was no evidence of publication bias found in the Begg's funnel plot or Egger's test. Sensitivity analyses showed that removal of individual studies had little impact on the pooled relarive risks for the outcomes.