Validation of a Modified CHA 2 DS 2 -VASc Score for Stroke Risk Stratification in Asian Patients With Atrial Fibrillation

Abstract

Background and Purpose— The age threshold for an increased stroke risk for patients with atrial fibrillation may be different for Asians and non-Asians. We hypothesized that a modified CHA 2 DS 2 -VASc (congestive heart failure, hypertension, age ≥75, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, age 65–74 years, female) scheme, mCHA 2 DS 2 -VASc, which assigned one point for patients aged 50 to 74 years, may perform better than CHA 2 DS 2 -VASc score for stroke risk stratification in Asians. Methods— This study used the Taiwan National Health Insurance Research Database, which included 224 866 newly diagnosed atrial fibrillation patients. The predictive accuracies of ischemic stroke of CHA 2 DS 2 -VASc and mCHA 2 DS 2 -VASc scores were compared among 124 271 patients without antithrombotic therapies. From the whole cohort, 15 948 patients had a CHA 2 DS 2 -VASc score 0 (males) or 1 (females), and 8654 patients had an mCHA 2 DS 2 -VASc score 1 (males) or 2 (females). The latter were categorized into 3 groups, that is, no treatment, antiplatelet therapy, and warfarin, and the risks of ischemic stroke and intracranial hemorrhage (ICH) were compared. Results— During a follow-up of 538 653 person-years, 21 008 patients experienced ischemic stroke. The mCHA 2 DS 2 -VASc performed better than CHA 2 DS 2 -VASc score in predicting ischemic stroke assessed by C indexes and net reclassification index. For 8654 patients having an mCHA 2 DS 2 -VASc score of 1 (males) or 2 (females) because of the resetting of the age threshold, use of warfarin was associated with a 30% lower risk of ischemic stroke and a similar risk of ICH compared with nontreatment. Net clinical benefit analyses also favored the use of warfarin in different weighted models. Conclusions— In this Asian atrial fibrillation cohort, the mCHA 2 DS 2 -VASc score performed better than the CHA 2 DS 2 -VASc and would further identify atrial fibrillation patients who may derive a positive net clinical benefit from oral anticoagulation.