Importance: The safety profile of interleukin (IL) inhibitors is not well established.
Objective: To assess the risk of serious infections, opportunistic infections, and cancer in patients with rheumatologic diseases treated with IL inhibitors.
Data sources: Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations; Ovid MEDLINE Daily; Ovid Embase; Ovid Cochrane Central Register of Controlled Trials; Ovid Cochrane Database of Systematic Reviews; and Scopus were searched (inception to November 30, 2018).
Study selection: Randomized, placebo-controlled trials that evaluated IL inhibitor therapies in rheumatic diseases and reported safety data were included in the analyses.
Data extraction and synthesis: This systematic review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Two investigators independently extracted study data and assessed risk of bias and certainty in the evidence. Fixed-effects meta-analysis was conducted to pool odds ratios (ORs) for serious infections, opportunistic infections, and cancers for IL inhibitors vs placebo.
Main outcomes and measures: The outcomes of interest were the number of serious infections, opportunistic infections, and cancers in individuals receiving IL inhibitor therapies compared with placebo.
Results: In this meta-analysis, 74 studies comprising 29 214 patients (24 236 patients for serious infections, 9998 for opportunistic infections, and 21 065 for cancer [number of patients overlaps for each outcome]) were included. Patients receiving IL inhibitors had a higher risk of serious infections (OR, 1.97; 95% CI, 1.58-2.44; P < .001, I2 = 0%; high certainty), opportunistic infections (OR, 2.35; 95% CI, 1.09-5.05; P = .03, I2 = 0%; moderate certainty), and cancer (OR, 1.52; 95% CI, 1.05-2.19; P = .03, I2 = 11%; moderate certainty).
Conclusions and relevance: The risk of serious infections, opportunistic infections, and cancer appears to be increased in patients with rheumatologic diseases who are treated with IL inhibitors compared with placebo.