Validation of the CHA2DS2-VA Score (Excluding Female Sex) in Nonvalvular Atrial Fibrillation Patients: A Nationwide Population-Based Study

Sex (i.e., female sex) confers one point for the CHA2DS2-VASc score. For this reason, females with atrial fibrillation (AF) always have a CHA2DS2-VASc score of at least 1. To compare the CHA2DS2-VA (excluding female sex) and CHA2DS2-VASc scores in Korean AF patients using the Korean National Health Insurance Service database, we analyzed the risk of ischemic stroke in nonvalvular AF patients between 2013 and 2017. The predictive values of the CHA2DS2-VA and CHA2DS2-VASc scores for ischemic stroke were evaluated using the C-statistic and net reclassification improvement (NRI). The primary outcome was the occurrence of ischemic stroke. A total of 185,637 patients with AF (49.7% women) were included in this study. The mean ages were 66.5 years for females and 64.9 years for males. The incidence of ischemic stroke in male patients was similar to females (3.63%/year vs. 3.72%/year, p = 0.273, respectively). In addition, no sex difference was apparent for stroke risk in AF patients stratified by risk factor component and age group. In the C-statistic analysis, the predictive ability of the CHA2DS2-VA score for ischemic stroke was similar to the CHA2DS2-VASc score. Additionally, CHA2DS2-VA performed better for predicting ischemic stroke in AF patients with risk scores of ≥2 (AUC 0.701 vs. 0.689, z = 4.596, p < 0.001) or those aged ≥75 years (AUC 0.715 vs. 0.701, z = 4.957, p < 0.001). In Korean AF patients, female sex is not a specific risk factor that contributes to the development of ischemic stroke. The CHA2DS2-VA score, which excludes female sex, may be a more suitable risk score for guiding anticoagulation decisions in Korean AF patients.