title: Validation of Risk Scoring System Excluding Female Sex From CHA2DS2-VASc in Japanese Patients With Nonvalvular Atrial Fibrillation – Subanalysis of the J-RHYTHM Registry.
abstract: BACKGROUND
  Because the current Japanese guideline recommends CHADS2 score-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 CHA2DS2-VASc and CHA2DS2-VA scores in the J-RHYTHM Registry.
  
  
  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 CHA2DS2-VASc and CHA2DS2-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 CHA2DS2-VASc and CHA2DS2-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 CHA2DS2-VA score being superior to the CHA2DS2-VASc score. In patients with CHA2DS2-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 CHA2DS2-VA to CHA2DS2-VASc score.
  
  
  CONCLUSIONS
  In Japanese NVAF patients, the CHA2DS2-VA score, a risk scoring system excluding female sex from CHA2DS2-VASc, may be more useful in risk stratification for thromboembolic events than CHA2DS2-VASc score, especially in identifying truly low-risk patients.
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tomita
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inoue
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Atarashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Hideki
authors.initials: H
authors.lastname: Origasa
authors.forename: Eiki
authors.initials: E
authors.lastname: Tsushima
mesh_terms: D000368:Aged; D044466:Asian People; D001281:Atrial Fibrillation / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D012042:Registries; D018570:Risk Assessment; D012737:Sex Factors; D013923:Thromboembolism / Q000453:epidemiology* / Q000209:etiology