Low prevalence of colonic mucosal injury and bleeding in patients taking direct oral anticoagulants for non-valvular atrial fibrillation.

Objective Direct oral anticoagulants are frequently used to prevent systemic embolism associated with atrial fibrillation. Gastrointestinal bleeding is a common adverse event of this pharmacotherapy, especially in the lower gastrointestinal tract. However, the prevalence of mucosal injury of the colon in patients taking direct oral anticoagulants has remained unknown. Materials and methods This was a retrospective study using endoscopic records of the colon from patients taking oral anticoagulants. Records from colonoscopies for 120 patients with non-valvular atrial fibrillation who had been prescribed direct oral anticoagulants between April 2011 and June 2017 were reviewed to determine the prevalence of mucosal injury and other findings, compared with those of 140 patients on warfarin. Results The prevalence of mucosal injury was 1.6% in patients taking direct oral anticoagulants and 1.4% in those taking warfarin, lower than other findings such as diverticula, hemorrhoids, and polyps. Bleeding was more frequent with direct oral anticoagulants (18 patients; 15%) than with warfarin (9 patients; 6.4%). Colonic diverticulum was the most common cause of bleeding in patients on direct oral anticoagulants. The prevalence of mucosal injury and causes of bleeding did not differ among direct oral anticoagulants. Conclusion Colonic mucosal injury was infrequent in patients on direct oral anticoagulants. Bleeding was more frequent with direct oral anticoagulants than with warfarin. Colonic diverticulum and vascular ectasia were common causes of bleeding in patients on direct oral anticoagulants. Little difference in cause of bleeding was evident among oral anticoagulants.