Predictive performance of the CHA2DS2‐VASc rule in atrial fibrillation: a systematic review and meta‐analysis

Essentials The widely recommended CHA2DS2‐VASc shows conflicting results in contemporary validation studies. We performed a systematic review and meta‐analysis of 19 studies validating CHA2DS2‐VASc. There was high heterogeneity in stroke risks for different CHA2DS2‐VASc scores. This was not explained by differences between setting of care, or by performing meta‐regression. Summary Background The CHA2DS2‐VASc decision rule is widely recommended for estimating stroke risk in patients with atrial fibrillation (AF), although validation studies show ambiguous and conflicting results. Objectives To: (i) review existing studies validating CHA2DS2‐VASc in AF patients who are not (yet) anticoagulated; (ii) meta‐analyze estimates of stroke risk per score; and (iii) explore sources of heterogeneity across the validation studies. Methods We performed a systematic literature review and random effects meta‐analysis of studies externally validating CHA2DS2‐VASc in AF patients not receiving anticoagulants. To explore between‐study heterogeneity in stroke risk, we stratified studies to the clinical setting in which patient enrollment started, and performed meta‐regression. Results In total, 19 studies were evaluated, with over two million person‐years of follow‐up. In studies recruiting AF patients in hospitals, stroke risks for scores of 0, 1 and 2 were 0.4% (approximate 95% prediction interval [PI] 0.2–3.2%), 1.2% (95% PI 0.1–3.8%), and 2.2% (95% PI 0.03–7.8%), respectively. These were consistently higher than those in studies recruiting patients from the open general population, with risks of 0.2% (95% PI 0.0–0.9%), 0.7% (95% PI 0.3–1.2%) and 1.5% (95% PI 0.4–3.3%) for scores of 0, 1, and 2, respectively. Heterogeneity, as reflected by the wide PIs, could not be fully explained by meta‐regression. Conclusions Studies validating CHA2DS2‐VASc show high heterogeneity in predicted stroke risks for different scores.