Efficacy of anti-tumor necrosis factor therapy for extra-articular manifestations in patients with ankylosing spondylitis: a meta-analysis

Background: We performed a meta-analysis to evaluate the effect of anti-tumor necrosis factor (TNF) therapy on the frequency of extra-articular manifestations (EAMs) in patients with ankylosing spondylitis (AS). Methods: We searched with the terms 'ankylosing spondylitis', 'infliximab', 'etanercept', 'adalimumab', 'golimumab', 'certolizumab', 'TNF inhibitor/blocker/antagonists' or 'anti-TNF' on MEDLINE, EMBASE and Cochrane Library for randomized controlled trials (RCTs) of >= 12 weeks with parallel or crossover design of TNF inhibitor versus placebo to treat uveitis, inflammatory bowel disease (IBD) and/or psoriasis of AS, published before February 2014. Results: We found 8 RCTs that fit our criteria. Anti-TNF therapy was associated with less uveitis than placebo in patients with AS (OR: 0.35, 95% CI: 0.15-0.81, P = 0.01). Subgroup analysis showed receptor fusion proteins were more efficacious for uveitis than placebo (OR: 0.30, 95% CI: 0.09-0.94, P = 0.04), but monoclonal antibodies were not (OR: 0.43, 95% CI: 0.12-1.49, P = 0.18). Anti-TNF therapy and placebo group did not significantly differ in treating IBD in AS patients (OR: 0.75, 95% CI: 0.25-2.29, P = 0.61). In subgroup analysis, neither monoclonal antibodies (OR: 0.45, 95% CI: 0.10-1.92, P = 0.28) nor receptor fusion proteins (OR: 1.52, 95% CI: 0.25-9.25, P = 0.65) significantly differed from placebo in treating IBD. We found no suitable reports on psoriasis. Conclusions: Anti-TNF therapy was preventive for flares or new onset of uveitis in AS patients, and might be an alternative for these patients. However, monoclonal anti-TNF antibodies and TNF receptor fusion proteins were not efficacious for IBD in AS patients.