Two validated scoring systems for predicting embolic risk, CHADS2 and CHA2DS2-VASc, contribute to optimizing antithrombotic prescription practices in patients who have atrial fibrillation. However, data about anticoagulated patients are sparse. We compared CHADS2 and CHA2DS2-VASc, in terms of their predictive risk evaluation, in patients with atrial fibrillation who were and were not taking anticoagulants. We systematically searched the Cochrane Library, PubMed, and Embase databases for studies of the comparative diagnostic performance of CHADS2 and CHA2DS2-VASc. We identified 12 cohort studies for meta-analysis. With regard to the occurrence of cardiovascular events individually, patients with CHA2DS2-VASc scores ≥2 have a greater risk of stroke (risk ratio [RR]=5.15; 95% confidence interval [CI], 3.85-6.88; P <0.00001) and thromboembolism (RR=5.96; 95% CI, 5.50-6.45; P <0.00001) (P diff=0.34) than do patients with CHA2DS2-VASc scores <2, independent of anticoagulation therapy (RR=5.76; 95% CI, 5.23-6.35; P <0.00001 in anticoagulated patients; and RR=6.12; 95% CI, 5.40-6.93; P <0.00001 in patients not taking anticoagulants; P diff=0.45). The pooled RR estimates indicate an approximate 6-fold increase in the risk of endpoint events in patients with CHA2DS2-VASc scores ≥2 (RR=5.90; 95% CI, 5.46-6.37; P <0.0001). These results clearly indicate the discriminative capacity of the CHA2DS2-VASc score for stroke, thromboembolic events, or both, independent of optimal anticoagulation. The CHA2DS2-VASc score enables the identification of patients who are at genuinely high risk and can direct the selection of appropriate therapeutic approaches.
Keywords: Atrial fibrillation/complications/epidemiology; decision support techniques; guidelines as topic; health status indicators; population surveillance/methods; predictive value of tests; randomized controlled trials as topic; risk assessment/methods/standards; stroke/epidemiology/prevention & control; thromboembolism/epidemiology/prevention & control.