Comparison of the severity of gastrointestinal bleeding among patients treated with warfarin and direct oral anticoagulants: nationwide cohort study

Introduction Previous studies have found higher rates of gastrointestinal bleeding (GIB) among patients on direct oral anticoagulants (DOACs) than warfarin. However, it remains unclear if severity of GIB varies between these drugs. We aimed to compare differences in severity of GIB between patients on warfarin and DOACs. Methods Using a national prescription database, all patients in Iceland receiving oral anticoagulants from 2014 to 2019 were identified. Data were collected on all GIB events among patients receiving oral anticoagulants during the study period from all five major hospitals in Iceland. The primary outcome was severe GIB, defined as the composite of any major GIB, endoscopic intervention, surgical intervention or transfusion. Results The study population included 709 patients; 46% (n=328) were on warfarin and 54% (n=381) on DOACs. The proportion of patients presenting with severe GIB was similar among patients receiving DOACs and warfarin (68% vs 71%, aOR 0.88, 95% CI 0.69 to 1.13). Compared with warfarin, DOAC users were less likely to receive anticoagulant reversal (4% vs 44%, aOR 0.05, 95% CI 0.03 to 0.08) or require hospitalisation (71% vs 77%, aOR 0.77, 95% CI 0.59 to 0.99) and more likely to receive only conservative treatment of their bleeding (47% vs 32%, aOR 1.83, 95% CI 1.45 to 2.31). There was no significant difference in mean haemoglobin drop, length of hospital stay, blood transfusion, endoscopic interventions or fatal GIB among the groups. Conclusion The severity of GIB in patients treated with warfarin and DOACs was comparable. The outcomes of patients diagnosed with GIB were similar in both groups.