Effect of anti-tumor necrosis factor α treatment on radiographic progression in patient with ankylosing spondylitis: A systematic review and meta-analysis

Background: Efficacy of anti-tumor necrosis factor (anti-TNF)α treatment in patient with active ankylosing spondylitis (AS) had been proved by many clinical studies. Inflammation and new bone formation in spine were two pivotal aspects in AS. TNF α inhibitor could eliminate inflammation including clinical and laboratory inflammatory manifestation. Paradoxical results whether TNF α antagonist could delay radiographic progression in AS were often been reported simultaneously. Objectives: To review the literature about the effect of TNF α inhibitor on radiographic progression and disease activity in patient with AS. Methods: We conducted a comprehensive search including Medline, EMBASE and the Cochrane Library from 1 January 2000 to 15 August 2017. Two reviewers independently supplemented with hand searching for the reference lists of inclusion. All trials focusing on radiographic progression or disease activity in patients with AS treated with anti-TNF α agents. Primary outcomes were modified Stokes AS Spinal Score (mSASSS), as well as Bath AS disease activity index (BASDAI) and Bath AS functional index (BASFI). Two reviewers independently selected studies and analyzed data. Methodological quality was assessed using the Newcastle-Ottawa scale (NOS). We pooled effects recorded on different scales as Standardized mean differences (SMDs) with 95% confidence intervals (CIs) using random-effects models. Results: We included 14 studies of low to moderate risk of bias with 3,186 patients, compared with control group, there was no effect of mSASSS changes (SMD = –0.12, 95% CI: –1.17–0.93, p value = .82, I2 = 95%) and follow-up (SMD = 0.03, 95% CI: 0.21–0.26, p value = .82, I2 = 36%) estimation in anti-TNF α group. However anti-TNF α agent treatment led to remarkable improvements on both Bath AS disease activity index (BASDAI) (SMD = 1.06, 95% CI: 0.22–1.89, p value = .01, I2 = 96%) and Bath AS functional index (BASFI) (SMD = 0.93, 95% CI: 0.24–1.92, p value = .01, I2 = 97%) scores at 12 weeks. Conclusion: Our meta-analysis found no significant effect on delaying radiographic progression in AS treated with TNF α inhibitor, although TNF α inhibitor could do improve significantly disease activity and physical function in AS.