Background:Because the current Japanese guideline recommends CHADS
2score-based risk stratification in nonvalvular atrial fibrillation (NVAF) patients and does not list female sex as a risk for thromboembolic events, we designed the present study to compare the CHA
2DS
2-VASc and CHA
2DS
2-VA scores in the J-RHYTHM Registry.
Methods and Results:We prospectively assessed the incidence of thromboembolic events for 2 years in 997 NVAF patients without warfarin treatment (age 68±12 years, 294 females). The predictive value of the CHA
2DS
2-VASc and CHA
2DS
2-VA scores for thromboembolic events was evaluated by c-statistic difference and net reclassification improvement (NRI). Thromboembolic events occurred in 7/294 females (1.2%/year) and 23/703 males (1.6%/year) (odds ratio 0.72 for female to male, 95% confidence interval (CI) 0.28–1.62, P=0.44). No sex difference was found in patient groups stratified by CHA
2DS
2-VASc and CHA
2DS
2-VA scores. There were significant c-statistic difference (0.029, Z=2.3, P=0.02) and NRI (0.11, 95% CI 0.01–0.20, P=0.02), with the CHA
2DS
2-VA score being superior to the CHA
2DS
2-VASc score. In patients with CHA
2DS
2-VASc scores 0 and 1 (n=374), there were markedly significant c-statistic difference (0.053, Z=6.6, P<0.0001) and NRI (0.11, 95% CI 0.07–0.14, P<0.0001), again supporting superiority of CHA
2DS
2-VA to CHA
2DS
2-VASc score.
Conclusions:In Japanese NVAF patients, the CHA
2DS
2-VA score, a risk scoring system excluding female sex from CHA
2DS
2-VASc, may be more useful in risk stratification for thromboembolic events than CHA
2DS
2-VASc score, especially in identifying truly low-risk patients. (
Circ J 2015;
79: 1719–1726)
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