CHAD65 and CHA2DS2-VASc Risk Stratification Tools for Patients with Atrial Fibrillation: A Review of Clinical Effectiveness and Guidelines

Key Message

Analysis using c-statistics showed that for patients with atrial fibrillation (AF) the CHADS2 and the CHA2DS2-VASc tools appear to perform similarly with respect to assessment of risk for stroke, thromboembolism or bleeding. Compared to the CHADS2, the CHA2DS2-VASc is better able to identify patients with very low risk of stroke or thromboembolism. No relevant studies on the CHAD65 algorithm were identified. The Canadian Cardiology Society (CCS) guideline recommended risk stratification using a predictive index for stroke and mentioned the CHAD65 algorithm as an example. In two guidelines (from the USA and the UK) the CHA2DS2-VASc score was recommended for assessing risk of stroke and in two guidelines (from the USA and Europe) it was not specifically mentioned that CHA2DS2-VASc score was recommended for assessing risk of stroke, however treatment recommendations were based on the CHA2DS2-VASc score. The CCS guideline recommended oral anticoagulant (OAC) therapy for most AF patients of age 65 years or CHADS2 1. Three guidelines recommended OAC therapy for AF patients with CHA2DS2-VASc 2. One guideline recommended OAC therapy for male AF patients with CHA2DS2-VASc 2 and female AF patients with CHA2DS2-VASc 3. However, the evidence supporting the recommendations was not described in the guideline reports.Findings need to be interpreted in the light of the described limitations.