Comparison Between CHADS<sub>2</sub> and CHA<sub>2</sub>DS<sub>2</sub>-VASc Score for Risk Stratification of Ischemic Stroke in Japanese Patients With Non-Valvular Paroxysmal Atrial Fibrillation Not Receiving Anticoagulant Therapy

Abstract

It remains unclear if the CHADS2 score or CHA2DS2-VASc score is more useful for the risk stratification of ischemic stroke/systemic thromboembolism in Japanese patients with non-valvular paroxysmal atrial fibrillation (NVPAF). We retrospectively investigated the incidence of ischemic stroke on the basis of CHADS2 and CHA2DS2-VASc scores in 332 NVPAF patients (224 men, mean age, 65 ± 13 years) who were not administered anticoagulation therapy before publication of the 2008 JCS guideline (mean follow-up period, 53 ± 35 months). Annual rates of ischemic stroke/ systemic thromboembolism underlying antiarrhythmic drug therapy were 0.2%/year for the 0-point group; 0.9%/year for the 1-point group; 2.8%/year for the 2-point group; 9.4 %/year for the 3-point group; and 10.9%/year for the ≥ 4-point group on the basis of the CHADS2 scores, and 0%/year for the 0-point group; 0.6%/year for the 1-point group; 1.0%/ year for the 2-point group; 2.0 %/year for the 3-point group; 5.5%/year for the 4-point group; 9.1%/year for the 5-point group; and 13.7%/year for the ≥ 6-point group on the basis of the CHA2DS2-VASc scores. Both higher CHADS2 and CHA2DS2-VASc scores were associated with greater annual rates of ischemic stroke/systemic thromboembolism (P < 0.001). In multivariate logistic regression analysis, the CHADS2 (odds ratio [OR]:4.74, 95% confidence interval [CI]:2.80-8.00, P < 0.001) and CHA2DS2-VASc scores (OR: 4.15, 95% CI:2.57-6.71, P < 0.001) were significant independent predictors for ischemic stroke/systemic thromboembolism. Area under the receiver-operator characteristic curves for predicting ischemic stroke/systemic thromboembolism were 0.89 in the CHA2DS2-VASc scores (P < 0.001) and 0.87 in the CHADS2 scores (P < 0.001). In Japanese patients with NVPAF, both the CHADS2 and CHA2DS2-VASc scores are useful parameters for the risk stratification of ischemic stroke/systemic thromboembolism.