Objective: To compare the effects of azathioprine and methotrexate on progression of radiologic damage in patients with rheumatoid arthritis.
Design: Double-blind, randomized 48-week trial.
Patients: Sixty-four patients with active rheumatoid arthritis who either have not responded to or who have reacted with side effects to at least parenteral gold and D-penicillamine.
Interventions: Either azathioprine, 100 mg daily, or methotrexate, 7.5 mg weekly, was administered orally. Depending on the clinical effect after 8 weeks, the dosage was increased to either azathioprine, 150 mg, or methotrexate, 15 mg. The dosages for nonsteroidal anti-inflammatory drugs and prednisone were held stable.
Measurements: Clinical and laboratory assessments were done by the same physician every 4 weeks for the first 24 weeks and every 8 weeks thereafter. Radiographs of hands, wrists, and feet obtained at baseline and after 24 and 48 weeks were scored by one rheumatologist blinded to medication and clinical findings.
Main results: Initial radiologic scores were comparable in both groups and correlated with disease duration (r = 0.38). An intention-to-treat analysis after 24 and 48 weeks showed significantly fewer new erosions in the methotrexate group compared with the azathioprine group (difference, 2.0 [95% CI, 0.2 to 3.9] and 3.5 [CI, 1.3 to 5.8], respectively). The change in total joint score was also significantly less pronounced in the methotrexate group compared with the azathioprine group after 24 weeks (difference, 2.8 [CI, 0.2 to 5.2]) and after 48 weeks (difference, 3.9 [CI, 0.3 to 7.4]). Radiologic stabilization after 48 weeks was present in 10% of the azathioprine group compared with 29% of the methotrexate group.
Conclusions: Patients with rheumatoid arthritis treated with low-dose methotrexate showed significantly less radiologic progression than patients treated with azathioprine. This result suggests that methotrexate therapy is clinically superior in these patients.