Use of Oral Anticoagulants for Stroke Prevention in Patients with Atrial Fibrillation Who Have a History of Intracranial Hemorrhage

Background-The risk of further intracranial hemorrhage (ICH) and the benefit of stroke risk reduction with the use of oral anticoagulants for patients who have atrial fibrillation with a history of ICH remain unclear. We aimed to investigate the risks and benefits in patients who have atrial fibrillation with a previous ICH treated with warfarin or antiplatelet drugs in comparison with no antithrombotic therapies. Methods and Results-This study used the National Health Insurance Research Database in Taiwan. Among 307 640 patients who have atrial fibrillation with a CHA₂DS₂-VASc score ≧2, 12 917 patients with a history of ICH were identified and were assigned to 1 of 3 groups, that is, no treatment, antiplatelet therapy, and warfarin. Among patients with previous ICH, the rate of ICH and ischemic stroke in untreated patients was 4.2 and 5.8 per 100 person-years, respectively. The annual ICH and ischemic stroke rates in warfarin users were 5.9% and 3.4%, respectively. Among users of antiplatelet agents, the rates were 5.3% per year and 5.2% per year, respectively. The number needed to treat for preventing 1 ischemic stroke was lower than the number needed to harm for producing 1 ICH with warfarin use for patients with a CHA₂DS₂-VASc score ≧6 (37 versus 56). The number needed to treat was higher than the number needed to harm for patients with a CHA₂DS₂-VASc score <6 (63 versus 53). Conclusions-Warfarin use may be beneficial for patients who have atrial fibrillation with a previous ICH having a CHA₂DS₂-VASc score ≧6. Whether the use of non-vitamin K antagonist oral anticoagulants could lower the threshold for treatment deserves further study.