Anticoagulants Are a Risk Factor for Delayed Bleeding after Colorectal Endoscopic Submucosal Dissection: A HASID Multicenter Study

Introduction: Delayed bleeding is an important adverse event following colorectal endoscopic submucosal dissection (ESD). However, whether anticoagulants are risk factors for delayed bleeding after colorectal ESD remains debatable. Methods: We retrospectively analyzed 1,708 patients who underwent colorectal ESDs between January 2015 and December 2020 at five academic medical centers in South Korea. We aimed to identify the risk factors for delayed bleeding in patients after colorectal ESD and, in particular, to evaluate the effect of anticoagulants. Results: Delayed bleeding occurred in 40 of 1,708 patients (2.3%). The risk factors for delayed bleeding were antithrombotic agents (odds ratio [OR], 6.155; 95% confidence interval [CI], 3.201-11.825; p < 0.001), antiplatelet agents (OR, 4.609; 95%CI, 2.200-9.658; p < 0.001), anticoagulants (OR, 8.286; 95% CI, 2.934-23.402; p < 0.001), and tumor location in the rectum (OR, 2.055; 95% CI, 1.085-3.897; p = 0.027). In the analysis that excluded patients taking antiplatelet agents, the delayed bleeding rate was higher in patients taking anticoagulants (1.6% no antithrombotic agents vs. 12.5% taking anticoagulants, p < 0.001). There was no difference in the delayed bleeding rate (4.2% direct oral anticoagulants vs. 25.0% warfarin, p = 0.138) or clinical outcomes according to the type of anticoagulant used. Conclusions: Anticoagulants use was a risk factor for delayed bleeding after colorectal ESD, and there was no difference in the risk of delayed bleeding based on the type of anticoagulant used. Colorectal ESD in patients receiving anticoagulants requires careful observation and management for delayed bleeding.