Among the many complications that can occur following therapeutic endoscopy, bleeding is the most serious, which occurs in 1.0-6.1% of all colonoscopic polypectomies. The aim of this study was to identify risk factors of delayed post-polypectomy bleeding (PPB).

We retrospectively reviewed the data of patients who underwent colonoscopic polypectomy between January 2003 and December 2012. We compared patients who experienced delayed PPB with those who did not. The control-to-patient ratio was 3:1. The clinical data analyzed included polyp size, number, location, and shape, patient' body mass index (BMI), preventive hemostasis, and endoscopist experience.

Of 1,745 patients undergoing colonoscopic polypectomy, 21 (1.2%) experienced significant delayed PPB. We selected 63 age- and sex-matched controls. Multivariate logistic regression analysis showed that polyps >10 mm (odds ratio [OR], 2.605; 95% confidence interval [CI], 1.035-4.528; P =0.049), a pedunculated polyp (OR, 3.517; 95% CI, 1.428-7.176; P =0.045), a polyp located in the right hemicolon (OR, 3.10; 95% CI, 1.291-5.761; P =0.013), and a high BMI (OR, 3.681; 95% CI, 1.876-8.613; P =0.013) were significantly associated with delayed PPB.

Although delayed PPB is a rare event, more caution is needed during colonoscopic polypectomies performed in patients with high BMI or large polyps, pedunculated polyps, or polyps located in the right hemicolon.