Venous and arterial thromboembolic risk of Janus kinase inhibitors: a systematic review with meta-analysis

Objective Preliminary data led licencing authorities to alert clinicians of an increased venous thrombotic risk associated to the use of Janus kinase (JAK) inhibitors (JAKi). We performed a systematic review to estimate the risk of venous and arterial thrombosis associated to JAKi for the treatment of immune-mediated inflammatory diseases (IMIDs). Methods Randomized controlled trials (RCTs) on JAKi in patients with IMIDs were identified by the MEDLINE and EMBASE databases until October 2021. Risk of bias was assessed according to Cochrane criteria. The beta-binomial model was applied to calculate pooled odds ratio (OR) and corresponding 95% CI. The PROSPERO registration number is CRD42022324143. Results We have included one phase I, 21 phase II, three phase II-III and 36 phase III RCTs for a total of 19 443 patients in the JAKi group and 6354 in the control group. Thirty-one (unweighted rate 0.16%; 95% CI: 0.10, 0.21) events were reported in the JAKi group and 20 (unweighted rate 0.22%; 95% CI: 0.12, 0.32) in the control group in a mean follow-up of 16.8 weeks. IMID patients treated with JAKi did not have an increased thromboembolic risk compared with those treated with placebo (OR 0.82; 95% CI: 0.43, 1.56). No statistically different results were seen in subanalyses for each investigated IMID, drug and dosage. Conclusion JAKi do not increase thromboembolic risk compared with placebo in IMID patients enrolled in selected RCTs.