A Korean nationwide cohort study by Tae-Hoon Kim et al has shown that truly low-risk Asian patients with atrial fibrillation (AF) for stroke can be identified using the CHA2DS2-VASc score. The study was published in the American Heart Association/American Stroke Association’s Stroke journal.
Non-vitamin K antagonist novel oral anticoagulants (NOACs) have effectively lowered the threshold of stroke risk for initiating other oral anticoagulants (OACs). Atrial fibrillation has long been treated with warfarin, an antigoagulant therapy which requires regular patient monitoring and has a higher risk of bleeding than NOACs, which may be a safer alternative with similar benefits to warfarin. As a result, prescription of NOACs such as apixaban has become prevalent in AF treatment.
As Kim et al note, “the focus of stroke prevention in patients with nonvalvular atrial fibrillation has shifted away from predicting high-risk patients toward initially identifying patients with a truly low risk of ischemic stroke, who do not need antithrombotic therapy.”
The follow-up study, which included a total of 5,855 OAC naive patients with nonvalvular AF over a period of 9-5 years, looked at methods of defining low-risk patients to limit unnecessary NOAC therapies. The study sample was based on patients aged 20 years or older enrolled in the Korea National Health Insurance Service-Sample Cohort database between January 2002 to December 2008 and followed up until December 2013.
The predictive ability of three risk stratification schemes were compared: congestive heart failure, hypertension, age ≥75, diabetes mellitus, prior stroke or transient ischemic attack (doubled; CHADS2), congestive heart failure, hypertension, age ≥75 (doubled), diabetes mellitus, prior stroke or transient ischemic attack (doubled), vascular disease, age 65 to 74, female (CHA2DS2-VASc), and Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA).
Kim et al conclude that the CHA2DS2-VASc score performed well and was a good tool for “defining truly low-risk Asian patients with atrial fibrillation for stroke compared with CHADS2 and ATRIA scores.”