Impact of CHADS₂ score on neurological severity and long-term outcome in atrial fibrillation-related ischemic stroke

Background and Purpose The CHADS₂ (an acronym for congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and prior stroke or transient ischemic attack or thromboembolism) score is a widely used system for estimating the risk of stroke in patients with atrial fibrillation. However, how the CHADS₂ score is related to stroke severity and outcome in patients with strokes due to atrial fibrillation has not yet been elucidated. Methods We enrolled patients with atrial fibrillation who visited our stroke center within 7 days after the onset of acute ischemic stroke between October 2002 and September 2008. CHADS₂ scores were categorized into three groups: 0 points, low risk; 1 or 2 points, intermediate risk; and 3-6 points, high risk. Poor neurological state was defined as follows: a National Institutes of Health Stroke Scale (NIHSS) score of ≥2, and a modified Rankin Scale (mRS) score of ≥3 at discharge. Mortality information was ascertained as at December 2008. Results A cohort of 298 patients with atrial-fibrillation-related stroke was included in this study. A high-risk CHADS2 score at admission was a powerful predictor of poor neurological outcome [for NIHSS: odds ratio (OR), 4.17; 95% confidence interval (CI), 1.76-9.87; for mRS: OR, 2.97; 95% CI, 1.23-7.16] after controlling for all possible confounders. In addition, a high-risk CHADS₂ score was an independent predictor of all causes of death during the follow-up [hazard ratio (HR), 3.01; 95% CI, 1.18-7.65] and vascular death (HR, 12.25; 95% CI, 1.50-99.90). Conclusions Although the CHADS₂ score was originally designed to distinguish patients with a future risk of stroke, our study shows that it may also be used to predict poor neurological outcome after atrial-fibrillation-related stroke.