Does the acetyl group of aspirin contribute to the antiinflammatory efficacy of salicylic acid in the treatment of rheumatoid arthritis

In a multicenter, study, 233 patients with classical or definite RA who demonstrated disease flare during a prestudy washout period were randomized to 12 weeks of treatment with either the nonacetylated salicylate, salsalate (salicylsalicylic acid), or aspirin. The efficacy of salsalate and aspirin was equivalent but aspirin-treated patients had a higher incidence of severe gastrointestinal problems