Efficacy of sulfasalazine in patients with inflammatory back pain due to undifferentiated spondyloarthritis and early ankylosing spondylitis: a multicentre randomised controlled trial.

ABSTRACT

OBJECTIVES: To assess the effect of sulfasalazine (SSZ) on inflammatory back pain (IBP) due to active undifferentiated spondyloarthritis (uSpA) or ankylosing spondylitis in patients with symptom duration <5 years. METHODS: Patients with IBP and a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) >3 from 12 centres were randomly assigned to 24 weeks' treatment with SSZ 2 g/day or placebo. The primary outcome variable was the change in BASDAI over 6 months. Secondary outcomes included measures of spinal pain, physical function and inflammation. RESULTS: 230 patients (50% men, age range 18-64 years, 67% human leucocyte antigen B27 positive) were treated with either SSZ 2x1 g/day or placebo for 6 months. Enthesitis was found in 50%, and peripheral arthritis in 47% of the patients. The mean (SD) BASDAI dropped markedly in both groups by 3.7 (2.7) and 3.8 (2.4), respectively, as did most secondary outcome measures. No noticeable difference in treatment was observed between groups. Patients with IBP and no peripheral arthritis had significantly (p = 0.03) more benefit with SSZ (BASDAI 5.1 (1.3) to 2.8 (2.3)) than with placebo (5.2 (1.6) to 3.8 (2.4)). Spinal pain (p = 0.03) and morning stiffness (p = 0.05) improved with SSZ in these patients, but other secondary outcomes were not markedly different. CONCLUSION: SSZ was no better than placebo for the treatment of the signs and symptoms of uSpA; however, SSZ was more effective than placebo in the subgroup of patients with IBP and no peripheral arthritis.