The role of CHADS2 and CHA2DS2-VASc scores in the prediction of stroke in individuals without atrial fibrillation: a population-based study

Background CHADS(2) and CHA(2)DS(2)-VASc are validated scores used to predict stroke in patients with atrial fibrillation (AF). We aimed to examine the performance of these scores in predicting stroke in individuals without AF. Methods Using the computerized database of the largest HMO in Israel, we identified all not-anticoagulated adults, aged 50 years or older on 1 January 2012. The cohort was followed for the occurrence of stroke or transient ischemic attack (TIA) until 31 December 2014. Results Of 1 053 871 individuals without AF at baseline, 34 215 developed stroke/TIA during a follow-up of 3 014 002 person-years (stroke/TIA incidence rate, 1.14 per 100 person-years). The incidence rate of stroke/TIA increased in a graded manner with increasing CHADS(2) score: 0.36, 0.89, 1.89, 2.96, 4.31, 5.37 and 6.62 per 100 person-years for CHADS(2) scores of 0 to 6 points, respectively (P < 0.001). Results were similar for the CHA(2)DS(2)-VASc score. A similar graded increasing trend in the stroke/TIA incidence rate was observed in a cohort of 46 657 patients with AF at baseline; however, stroke/TIA rates were higher in each score stratum compared with the rates of individuals without AF. The area under the receiver operating characteristic curve was 0.718 (95% CI, 0.715-0.721) and 0.714 (0.711-0.717) for CHADS(2) and CHA(2)DS(2)-VASc scores, respectively, in individuals without AF, and 0.606 (0.598-0.614) and 0.610 (0.602-0.618), respectively, in individuals with AF. Conclusions CHADS(2) and CHA(2)DS(2)-VASc scores have a relatively high performance for prediction of stroke/TIA in individuals without AF, which is comparable to their performance in patients with AF.