Risk of Venous Thromboembolism Associated With Tofacitinib and Baricitinib: A Systematic Review and Indirect Meta-Analysis

To conduct a systematic review and meta-analysis investigating the effect of tofacitinib and baricitinib on venous thromboembolism (VTE) risk. Search of PubMed, EMBASE, Web of Science, Scopus, ClinicalTrials.gov, LILACS, and Google Scholar databases to identify controlled observational and clinical trials reporting on adverse effects in patients treated with oral tofacitinib or baricitinib up to July 2020. The outcome measure was occurrence of VTE events. We analyzed 59 studies involving 14,335 patients treated with tofacitinib or baricitinib and 11,612 patients who received another active drug or placebo. The meta-analysis showed an odds ratio (OR) for VTE events of 0.29 (95% confidence interval [CI] = 0.10-0.84) overall for tofacitinib based on data from 10 clinical trials with 15 treatment arms; similar ORs were observed for the 10 mg/d dose (OR = 0.18; 95% CI = 0.02-1.60) and the 20 mg/d dose (OR = 0.19; 95% CI = 0.04-0.91). The ORs for VTE events for baricitinib were 3.39 (95% CI = 0.82-14.04) overall, 3.05 (95% CI = 0.12-75.43) for 2 mg, 3.64 (95% CI = 0.59-22.46) for 4 mg, and 3.0 (95% CI = 0.12-76.49) for 7 mg. The indirect meta-analysis comparing tofacitinib with baricitinib (10 clinical trials with 15 treatment arms) showed an OR for VTE events of 0.086 (95% CI = 0.02-0.51) for tofacitinib and a superior safety profile for VTE events. In the meta-regression analysis (19 clinical trials with 21 treatment arms), the effect was 0.02 (95% CI = -0.04 to 0.08) for tofacitinib and -0.01 (95% CI = -1.29 to 1.26 for baricitinib. Plotting of the data for tofacitinib showed that VTE risk increased with high doses. The effect, however, was less than 1 for the 10-mg and 20-mg doses, indicating a protective effect. This effect was not observed for baricitinib. Tofacitinib is not associated with an increased risk of VTE and has a superior safety profile to baricitinib in this respect. Tofacitinib may exert a protective effect against VTE.