The association of drugs with severity and specific causes of acute lower gastrointestinal bleeding: A prospective study

Objectives: Studies on the association of acute lower gastrointestinal bleeding (ALGIB) and drugs are scarce. We aimed to investigate the association of drugs and ALGIB, especially regarding specific causes of ALGIB, and their role in the severity of ALGIB. Materials and Methods: The study was prospective and included all patients undergoing colonoscopy in 2010 and 2013 at the National University Hospital of Iceland. Use of nonsteroidal anti-inflammatory drugs (NSAIDs), low-dose aspirin (LDA), and warfarin before ALGIB was registered. Clinically significant bleeding was defined as: hemoglobin <100 g/L, hemodynamic instability, blood transfusion, surgery, or death. Results: Overall, 2392 patients underwent 2751 colonoscopies, of those, 325 (14%) had ALGIB, mean age 64 years (±20). The commonest diagnoses were diverticulosis (22%) and ischemic colitis (14%). In multivariate analysis, NSAIDs, LDA, and warfarin use was associated with ALGIB, odds ratio (OR) 3.3 [95% confidence interval (95% CI), 1.99-5.82], OR 1.5 (95% CI, 1.01-2.13), and OR 2.7 (95% CI, 1.61-4.57), respectively. Clinically significant bleeders were more likely than nonclinically significant bleeders to use NSAIDs or LDA+warfarin, OR 2.3 (95% CI, 1.26-3.76) and OR 33.0 (95% CI, 6.74-595), respectively. Patients with diverticular bleeding had greater odds than controls of NSAID, LDA, and warfarin use, OR 8.3 (95% CI, 3.8-18.3), OR 2.1 (95% CI, 1.15- 3.67), and OR 2.6 (95% CI, 1.24-5.56), respectively. Patients with ischemic colitis were more likely than controls to use LDA, OR 2.3 (95% CI, 1.14-4.45). Conclusions: NSAIDs, LDA, and warfarin were associated with ALGIB and diverticular bleeding. These drugs may have a role in other etiologies of ALGIB and seem to increase the risk of clinically significant bleeding.