Salsalate, a nonacetylated salicylate, is as efficacious as diclofenac in patients with rheumatoid arthritis. Salsalate-Diclofenac Study Group

OBJECTIVE: To investigate the efficacy of salsalate, a nonacetylated salicylate, in the treatment of patients with rheumatoid arthritis (RA). METHODS: Three hundred and one patients meeting the ACR criteria for RA were drawn from 16 centers. After withdrawal of nonsteroidal antiinflammatory drugs (NSAID) and subsequent flare, patients were randomized to receive either salsalate or diclofenac for 8 weeks, according to a double blind, double dummy protocol. Initial doses of salsalate 3.0 g/day and diclofenac 75 mg/day were titrated for the first 5 weeks. The primary outcome measure was a multivariate analysis at 8 weeks of tender joint count, pain, visual analog scale score, and physician's global assessment. RESULTS: One hundred and ninety patients completed the study. The mean stabilized dose of salsalate was 3.55 g/day, and that of diclofenac 112 mg/day. Discontinuations were due to lack of efficacy (17 salsalate vs 15 diclofenac); adverse events 19 salsalate (mainly tinnitus and hearing loss; p = 0.0001 and p = 0.04, respectively) vs 9 diclofenac]; laboratory abnormalities (3 salsalate vs 1 diclofenac); and other reasons, including protocol violations, intercurrent illness, and personal factors (24 salsalate vs 23 diclofenac). Both treatments produced significant improvement from flare (p < 0.0001). Post hoc power analysis showed that the study had sufficient power (0.60 to 0.90) to detect clinically important differences between the 2 drugs in the primary outcome measures; however, no statistically significant (p = 0.29) or clinically important treatment differences were recorded. Other than a difference in erythrocyte sedimentation rate that favored salsalate, there were no significant differences in secondary outcome measures between the 2 groups. All outcomes showed a tendency for more improvement with salsalate. CONCLUSION: Salsalate is as efficacious as diclofenac. Salsalate may be considered an alternative to other NSAID in the first line treatment of patients with RA.