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

Abstract

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. 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). 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.