Patients with inflammatory bowel disease (IBD) have a more than twofold higher risk of venous thromboembolic events (VTE) than the general population. The etiology is complex, and the role of medication is not precisely defined.We aimed to assess the effect of anti-tumor necrosis factor alpha (anti-TNFα) drugs and conventional anti-inflammatory therapy, namely corticosteroids (CS), immunomodulators (IM), and 5-aminosalicylates (5-ASA) on VTE in IBD.
A systematic search was performed in five databases on the 22nd of November 2022. We included studies reporting VTE in the distinct categories of medications, determined the proportions, and calculated the odds ratios (OR) with 95% confidence intervals (CI), using the random-effects model. The risk of bias was evaluated with the Joanna Briggs Institute Critical Appraisal Checklist and the Risk of Bias in Non-randomized Studies of Interventions tool.
The quantitative analysis included 16 observational studies, with data from 91,322 IBD patients. Patients receiving anti-TNFα medication had significantly less VTE (proportion: 0.05, CI: 0.02-0.10), than patients treated with CS (proportion: 0.16, CI: 0.07-0.32), with OR=0.42 (CI: 0.25-0.71). IMs resulted in similar proportions of VTE compared with biologics (0.05, CI: 0.03-0.10), with OR=0.94 (CI: 0.67-1.33). The proportion of patients receiving 5-ASA having VTE was 0.09 (CI: 0.04-0.20), with OR=1.00 (CI: 0.61-1.62).
Biologics should be preferred over corticosteroids in cases of severe flare-ups and multiple VTE risk factors, as they are associated with reduced odds of these complications. Further studies are needed to validate our data.

© The Author(s) 2023. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation.