Usefulness of CHADS2 and CHA2DS2-VASc Scores in the Prediction of New-Onset Atrial Fibrillation: A Population-Based Study

Background: CHADS2 and CHA2DS2-VASc are validated scores used to predict stroke in patients with atrial fibrillation. Many of the individual risk factors included in these scores are also risk factors for atrial fibrillation. We aimed to examine the performance of CHADS2 and CHA2DS2-VASc scores in predicting new-onset atrial fibrillation in subjects without preexisting diagnosis of atrial fibrillation.

Methods: Using the computerized database of the largest health maintenance organization in Israel, we identified all adults aged 50 years or older without atrial fibrillation prior to January 1, 2012. CHADS2 and CHA2DS2-VASc scores were calculated for each participant at study entry, and the cohort was followed for incident atrial fibrillation until December 31, 2014.

Results: Of 1,062,073 subjects without preexisting diagnosis of atrial fibrillation; 23,223 developed atrial fibrillation during a follow-up of 3,053,754 person-years (incidence rate, 0.76 per 100 person-years). Incidence rate of atrial fibrillation increased in a graded manner with increasing CHA2DS2-VASc score: 0.17, 0.21, 0.49, 0.94, 1.65, 2.31, 2.75, 3.39, 4.09, and 6.71 per 100 person-years for CHA2DS2-VASc score of 0 to 9 points, respectively (P < .001). The hazard ratio for atrial fibrillation for each 1-point increase in CHA2DS2-VASc score was 1.57 (95% confidence interval [CI], 1.56-1.58). Results were similar for CHADS2 score. The area under the receiver operating characteristic curve to predict new-onset atrial fibrillation was 0.728 (95% CI, 0.725-0.711) and 0.744 (95% CI, 0.741-0.747) for CHADS2 and CHA2DS2-VASc scores, respectively.

Conclusions: CHADS2 and CHA2DS2-VASc scores are directly associated with the incidence of new-onset atrial fibrillation, and have a relatively high performance for atrial fibrillation prediction.