Restarting anticoagulant therapy after intracranial hemorrhage in patients with atrial fibrillation: A nationwide retrospective cohort study.

BACKGROUND: Resuming anticoagulation after an intracranial hemorrhage (ICH) poses a clinical conundrum. The absence of relevant guidelines has led to wide variations in the decision on resuming anticoagulation therapies after ICH. This study aimed to evaluate the risks of an anticoagulation therapy on severe thrombotic events (STE) and severe hemorrhage events (SHE) in Korea and compare the effects of novel direct oral anticoagulants (NOACs) and warfarin in patients with AF.

METHODS: This study was performed using the Korean national health insurance claims data obtained between 2002 and 2017 from individuals who had recently survived an ICH with comorbid AF. The endpoints of this study were STE and SHE. Anticoagulants, antiplatelet agents, and non-antithrombotic users were analyzed for survival with propensity score matching.

RESULTS: Among the 4,964 participants analyzed, 878 (17.7%) and 2,070 (41.7%) used anticoagulant and antiplatelet agents, respectively. Anticoagulant (hazard ratio [HR] for STE: 0.385, P  < 0.0001; HR for SHE: 0.578, P  < 0.0001) or antiplatelet users (HR for STE: 0.545, P  < 0.0001; HR for SHE: 0.637, P  < 0.0001) had a lower risk of STE and SHE than non-antithrombotic users. Anticoagulation 6-8 weeks post-ICH showed a tendency of the lowest risk of all-cause mortality (HR: 0.614, P = 0.0552). However, there was no difference in the risk between the anticoagulant and antiplatelet users. Further, NOACs were associated with a lower risk of STEs than warfarin (HR, 0.263; P  < 0.0001).

CONCLUSIONS: Our results showed that in patients with AF, resuming anticoagulants and antiplatelets after ICH improved the STEs and SHEs. Further, NOAC had additional benefits as compared to warfarin.