Heterogeneity in Comparisons of Discontinuation of Tumor Necrosis Factor Antagonists in Rheumatoid Arthritis - A Meta-Analysis

Objective
We did a systematic review of studies comparing discontinuation of tumor necrosis factor alpha (TNF) antagonists in rheumatoid arthritis (RA) patients, pooled hazard ratios and assessed clinical and methodological heterogeneity.
Methods
We searched MEDLINE and EMBASE until June 2015 for pairwise hazard ratios for discontinuing infliximab, etanercept, and adalimumab from cohorts of RA patients. Hazard ratios were pooled using inverse variance weighting and random effects estimates of the combined hazard ratio were obtained. Clinical and methodological heterogeneity was assessed using the between-subgroup I-square statistics and meta-regression.
Results
Twenty-four unique studies were eligible and large heterogeneity (I-square statistics > 50%) was observed in all comparisons. Type of data, location, and order of treatment (first or second line) modified the magnitude and direction of discontinuation comparing infliximab with either adalimumab or etanercept; however, some heterogeneity remained. No effect modifier was identified when adalimumab and etanercept were compared.
Conclusion
Heterogeneity in studies comparing discontinuation of TNF antagonists in RA is partially explained by type of data, location, and order of treatment. Pooling hazard ratios for discontinuing TNF antagonists is inappropriate because largely unexplained heterogeneity was demonstrated when random effect estimates were calculated.