title: CHADS2 versus CHA2DS2-VASc score in assessing the stroke and thromboembolism risk stratification in patients with atrial fibrillation: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To perform a systematic review and meta-analysis of the predictive abilities of CHADS2 and CHA2DS2-VASc in stroke and thromboembolism risk stratification of atrial fibrillation (AF) patients.
  
  
  METHODS
  We searched PubMed and EMBASE for English-language literature on comparisons of the diagnostic performance between CHADS2 and CHA2DS2-VASc in predicting stroke, or systemic embolism, in AF. We then assessed the quality of the included studies and pooled the C-statistics and 95% confidence intervals (95% CI).
  
  
  RESULTS
  Eight studies were included. It was unsuitable to perform a direct meta-analysis because of high heterogeneity. When analyzed as a continuous variable, the C-statistic ranged from 0.60 to 0.80 (median 0.683) for CHADS2 and 0.64-0.79 (median 0.673) for CHA2DS2-VASc. When analyzed as a continuous variable in anticoagulation patients, the subgroup analysis showed that the pooled C-statistic (95% CI) was 0.660 (0.655-0.665) for CHADS2 and 0.667 (0.651-0.683) for CHA2DS2-VASc (no significant difference). For non-anticoagulation patients, the pooled C-statistic (95% CI) was 0.685 (0.666-0.705) for CHADS2 and 0.675 (0.656-0.694) for CHA2DS2-VASc (no significant difference). The average ratio of endpoint events in the low-risk group of CHA2DS2-VASc was less than CHADS2 (0.41% vs. 0.94%, P < 0.05). The average proportion of the moderate-risk group of CHA2DS2-VASc was lower than CHADS2 (11.12% vs. 30.75%, P < 0.05).
  
  
  CONCLUSIONS
  The C-statistic suggests a similar clinical utility of the CHADS2 and CHA2DS2-VASc scores in predicting stroke and thromboembolism, but CHA2DS2- VASc has the important advantage of identifying extremely low-risk patients with atrial fibrillation, as well as classifying a lower proportion of patients as moderate risk.
authors.affiliation: Department of Cardiology, the First Affiliated Hospital of Jinan University Guangzhou, Guangdong 510630, China.
authors.forename: Jia-Yuan
authors.initials: JY
authors.lastname: Chen
authors.forename: Ai-Dong
authors.initials: AD
authors.lastname: Zhang
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Lu
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Wang
authors.forename: Zi-Cheng
authors.initials: ZC
authors.lastname: Li
keywords: Atrial fibrillation; CHA2DS2-VASc; CHADS2; Meta-analysis; Prediction; Stroke