The CHADS2 and CHA2DS2-VASc scores for predicting ischemic stroke among East Asian patients with atrial fibrillation: A systemic review and meta-analysis

BACKGROUND: Both the CHADS2 and CHA2DS2-VASc scores are well-validated in Western populations for predicting risk of stroke among patients with atrial fibrillation (AF). There is some uncertainty as to which risk score is best to guide optimal anticoagulant therapy among Asian populations with AF.

METHODS: A systemic literature search of Cochrane library, Scopus, and PubMed databases was conducted using search terms: atrial fibrillation, CHADS2 and CHA2DS2-VASc. Stroke/thromboembolism (TE) outcome events at low, moderate, and high risk groups were compared in relation to both scores. Statistical analyses were performed using Revman 5.3 software.

RESULTS: 493 records were retrieved, of which 6 cohort studies focusing on patients from Asian regions were finally appraised and included. Absolute event rates were usually lower when patients were categorized as CHA2DS2-VASc of 0-1, rather than CHADS2 of 0-1, respectively. Meta-analysis revealed that when compared with the CHA2DS2-VASc score, there was a 1.71-fold elevated risk of stroke when patients were stratified as 'low risk' using a CHADS2 score=0, or a 1.40-fold increase with a CHADS2 score=1. A 1.19-fold elevated event rate was observed among CHADS2 score ≥2 compared to CHA2DS2-VASc, but the total stroke/TE events were numerically higher in patients categorized as CHA2DS2-VASc ≥2.

CONCLUSION: The CHA2DS2-VASc score is superior to the CHADS2 score in identifying 'low risk' East Asian AF patients. Rather than a categorical approach, Asian guidelines should adopt a 2 step approach, by initially identifying the truly low risk patients, following which effective stroke prevention can be offered to those with ≥1 additional stroke risk factors.