Patients With Ischemic Stroke and Incident Atrial Fibrillation: A Nationwide Cohort Study.

BACKGROUND AND PURPOSE A substantial part of ischemic strokes is attributed to atrial fibrillation (AF). We hypothesized that patients with ischemic stroke without prior diagnosed AF were at higher risk of having a subsequent diagnosis of AF, and this was associated with multiple risk factors. METHODS This French longitudinal cohort study was based on the national database covering hospital care from 2008 to 2012 for the entire population. RESULTS Of 65 807 patients with ischemic stroke in 2009, 48 992 did not have AF at baseline. A total of 4828 of these patients were diagnosed as having AF during a follow-up of 15±15 months (incidence rate 7.9 per 100 person-years). By comparison, the yearly rate of new-onset AF for the 826 416 patients with a cardiac hospitalization was 5.9%. CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack) and CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack [doubled], vascular disease, age 65-75 years, and sex category [female]) scores were both associated with the risk of new-onset AF during follow-up (CHADS2: hazard ratio [HR] 1.70, 95% confidence interval [CI] 1.66-1.75; CHA2DS2-VASc: HR 1.45, 95% CI 1.42-1.48). The c statistics were 0.700 (95% CI 0.696-0.706) for CHADS2 and 0.706 (95% CI 0.702-0.710) with CHA2DS2-VASc (P=0.003 for comparison of the 2 scores). Independent predictors of subsequent diagnosis of AF were age 65 to 74 years (HR 2.29, 95% CI 2.06-2.54), age ≥75 years (HR 3.31, 95% CI 3.02-3.64), hypertension (HR 1.22, 95% CI 1.13-1.32), heart failure (HR 2.56, 95% CI 2.41-2.72), and vascular disease (HR 1.10, 95% CI 1.04-1.17). CONCLUSIONS Ischemic stroke was associated with a substantially increased risk of incident AF, particularly among individuals with higher CHADS2 or CHA2DS2-VASc scores. These risk scores seem to be simple tools for identifying patients at higher risk of incident AF after ischemic stroke.