Risk of Postcolonoscopy Thromboembolic Events: A Real-World Cohort Study

Although antithrombotic agents could increase the risk of postpolypectomy bleeding, interruption of these agents also increases the risk of thromboembolism (TE). We assessed the risks of postcolonoscopy TE events and their association with the interruption of antithrombotic agents.

This was a retrospective cohort study including consecutive patients undergoing colonoscopy between January 2016 and March 2021. We determined the rates of postcolonoscopy TE events in patients taking various antithrombotic agents (with or without interruption), and in different patient groups according to indications for colonoscopy, underlying TE, and bleeding risks.

Of the 6220 patients, 1755 (28.2%) were on antithrombotics. Overall, 20 patients (0.32%) developed TE events, and 25 (0.80%) of 3134 patients with polypectomy experienced major episodes of bleeding. Among all patients on antithrombotic agents, the highest rates of TE events were observed in patients on dual-antiplatelet therapy (4.65%; adjusted odds ratio [aOR], 28.0; 95% CI, 3.77-142.1) and clopidogrel (2.78%; aOR, 12.2; 95% CI, 2.10-57.0), compared with 0.11% among those not on antithrombotics. In patients interrupting anti-thrombotic agents, the risk of TE was increased compared to those on no agent as follows: stopping 2 or more antithrombotic agents (4.55%; aOR, 22.5; 95% CI, 1.09-158.0), monotherapy with clopidogrel (3.06%; aOR, 15.5; 95% CI, 2.86-69.6), warfarin (1.33%; aOR, 6.96; 95% CI, 1.14-33.5), or direct-acting oral anticoagulants (0.87%; aOR, 6.23; 95% CI, 1.22-26.8). Having an underlying high TE risk (aOR, 16.8; 95% CI, 6.33-46.6) was associated with higher postcolonoscopy TE events.

The risk of post-colonoscopy thromboembolic events is low. However, the temporary interruption of antithrombotic agents, particularly stopping 2 or more agents, clopidogrel, warfarin, or direct-acting oral anticoagulants was associated with higher postcolonoscopy TE events, particularly in high-risk patients.