CHADS2 versus CHA2DS2-VASc score in assessing the stroke and thromboembolism risk stratification in patients with atrial fibrillation: a systematic review and meta-analysis

Objective To perform a systematic review and meta-analysis of the predictive abilities of CHADS(2) and CHA(2)DS(2)-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 CHADS(2) and CHA2DS(2)-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 CHADS(2) 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 CHA2DS(2)-VASc (no significant difference). For non-anticoagulation patients, the pooled C-statistic (95% CI) was 0.685 (0.666-0.705) for CHADS(2) 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 CHA2DS(2)-VASc was less than CHADS(2) (0.41% vs. 0.94%, P < 0.05). The average proportion of the moderate-risk group of CHA2DS(2)-VASc was lower than CHADS(2) (11.12% vs. 30.75%, P < 0.05). Conclusions The C-statistic suggests a similar clinical utility of the CHADS(2) and CHA2DS(2)-VASc scores in predicting stroke and thromboembolism, but CHA2DS(2)-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.