Gastrointestinal bleeding in patients with atrial fibrillation treated with Apixaban or warfarin: Insights from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial

Abstract

A history of gastrointestinal bleeding (GIB) in patients with atrial fibrillation (AF) may impact decisions about anticoagulation treatment. We sought to determine whether prior GIB in patients with AF taking anticoagulants was associated with an increased risk of stroke or major hemorrhage. We analyzed key efficacy and safety outcomes in patients with prior GIB in ARISTOTLE. Centrally adjudicated outcomes according to GIB history were analyzed using Cox proportional hazards models adjusted for randomized treatment and established risk factors. A total of 784 (4.3%) patients had prior GIB events (321 [41%] lower, 463 [59%] upper); 215 (27%) occurred <1 year before study enrollment. Patients with prior GIB were older, had more comorbidities, and higher CHADS2 and HAS-BLED scores than those with no GIB. Major GIB occurred more frequently in those with prior GIB (lower: aHR 1.72, 95% CI 0.86-3.42; upper: aHR 3.13, 95% CI 1.97-4.96). This association with major GIB was more pronounced in patients with GIB <1 year before randomization versus no recent GIB (recent lower: aHR 2.58, 95% CI 0.95-7.01; recent upper: aHR 5.16, 95% CI 2.66-10.0). There was no association between prior GIB and risk of stroke/systemic embolism or all-cause death. In those with prior GIB, the apixaban versus warfarin relative risks for stroke/systemic embolism, hemorrhagic stroke, death, or major bleeding were consistent with the results of the overall trial. In patients with AF on oral anticoagulants, prior GIB was associated with an increased risk of subsequent major GIB but not stroke, intracranial bleeding, or all-cause mortality. For the key outcomes of stroke, hemorrhagic stroke, death, and major bleeding, we found no evidence that the treatment effect (apixaban vs. warfarin) was modified by a history of GIB.