Risk of both intracranial hemorrhage and ischemic stroke in elderly individuals with nonvalvular atrial fibrillation taking direct oral anticoagulants compared with warfarin: Analysis of the ANAFIE registry

Background and aims: Elderly patients with nonvalvular atrial fibrillation (NVAF) might have a higher risk of intracerebral hemorrhage. To investigate this, we compared the incidence of intracranial hemorrhage (ICH) and its subtypes, as well as ischemic stroke, in patients taking direct oral anticoagulants (DOACs) compared with warfarin in a real-world setting. We also determined the baseline characteristics associated with both ICH and ischemic stroke. Methods: Patients aged > 75 years with documented NVAF enrolled in the prospective, multicenter, observational All Nippon Atrial Fibrillation in the Elderly Registry between October 2016 and January 2018 were evaluated. The co-primary endpoints were the incidence of ischemic stroke and ICH. Secondary endpoints included subtypes of ICH. Results: Of 32,275 patients (13,793 women; median age, 81.0 years) analyzed, 21,585 (66.9%) were taking DOACs and 8233 (25.5%) were taking warfarin. During the median 1.88-year follow-up, 743 patients (1.24/100 person-years) developed ischemic stroke and 453 (0.75/100 person-years) developed ICH (intracerebral hemorrhage, 189; subarachnoid hemorrhage, 72; subdural/epidural hemorrhage, 190; unknown subtype, 2). The incidence of ischemic stroke (adjusted hazard ratio (aHR) 0.82, 95% confidence interval (CI) 0.70-0.97), ICH (aHR 0.68, 95% CI 0.55-0.83), and subdural/epidural hemorrhage (aHR 0.53, 95% CI 0.39-0.72) was lower in DOAC users versus warfarin users. The incidence of fatal ICH and fatal subarachnoid hemorrhage was also lower in DOAC users versus warfarin users. Several baseline characteristics other than anticoagulants were also associated with the incidence of the endpoints. Of these, history of cerebrovascular disease (aHR 2.39, 95% CI 2.05-2.78), persistent NVAF, (aHR 1.90, 95% CI 1.53-2.36), and long-standing persistent/permanent NVAF (aHR 1.92, 95% CI 1.60-2.30) was strongly associated with ischemic stroke; severe hepatic disease (aHR 2.67, 95% CI 1.46-4.88) was strongly associated with overall ICH; and history of fall within 1 year was strongly associated with both overall ICH (aHR 2.29, 95% CI 1.76-2.97) and subdural/epidural hemorrhage (aHR 2.90, 95% CI 1.99-4.23). Conclusion: Patients aged > 75 years with NVAF taking DOACs had lower risks of ischemic stroke, ICH, and subdural/epidural hemorrhage than those taking warfarin. Fall was strongly associated with the risks of intracranial and subdural/epidural hemorrhage. Data access statement: The individual de-identified participant data and study protocol will be shared for up to 36 months after the publication of the article. Access criteria for data sharing (including requests) will be decided on by a committee led by Daiichi Sankyo. To gain access, those requesting data access will need to sign a data access agreement. Requests should be directed to yamt-tky@umin.ac.jp.