Abstract P609: Restarting Anticoagulant Therapy After Intracranial Hemorrhage With Atrial Fibrillation: A Nationwide Retrospective Cohort Study

Background: Atrial fibrillation (AF) should be treated with anticoagulants to prevent stroke and systemic embolism. Resuming anticoagulation after intracerebral hemorrhage (ICH) poses a clinical conundrum. The absence of evidence-based guidelines to address this issue has led to wide variations in restarting anticoagulation after ICH. This study aimed to evaluate the risks and benefits of anticoagulation therapy on all-cause mortality, severe thromboembolism, and severe hemorrhage and compare the effect of novel direct oral anticoagulants (NOACs) with warfarin on post-ICH mortality in patients with AF. Methods: This retrospective cohort study was performed using health insurance claim data obtained between 2002 and 2017 from individuals with newly developed ICH with comorbid AF. We excluded participants aged < 40 years and those with traumatic ICH, subdural hemorrhage, or subarachnoid hemorrhage. The primary endpoint was all-cause mortality, and the secondary endpoints were severe thrombotic and hemorrhagic events. Anticoagulants, antiplatelet agents, and non-users were analyzed for survival with propensity score matching. Results: Among 6735 participants, 1743 (25.9%) and 1690 (25.1%) used anticoagulants and antiplatelet agents, respectively. Anticoagulant (HR, 0.321; 95% CI, 0.264-0.390; P < 0.0001) or antiplatelet users (HR, 0.393; 95% CI, 0.330-0.468; P < 0.0001) had a lower risk of all-cause mortality than non-users. However, there was no difference between the two drug users (HR, 1.183; 95% CI, 0.94-1.487; P = 0.152; reference: anticoagulant). The risk of acute thrombotic events, although not hemorrhagic events, was significantly lower in anticoagulant users than in antiplatelet users. In addition, anticoagulation between 6 to 8 weeks post-ICH showed a tendency of the lowest risk of death. Further, NOACs were associated with a lower risk of all-cause mortality than warfarin. Conclusions: Our results showed that in patients with AF, resuming anticoagulants between 6 and 8 weeks after ICH improved all-cause mortality, severe thromboembolism, and severe hemorrhage. Further, compared with warfarin, NOAC had additional benefits.