Refinement of Ischemic Stroke Risk in Patients with Atrial Fibrillation and CHA2DS2‐VASc Score of 1

BACKGROUND: Patients with atrial fibrillation (AF) with CHA2 DS2 -VASc score of 1 (where CHA2 DS2 -VASc is CHA2 DS2 -Vascular disease, Age 65-74 years, Sex category) are recommended to receive antithrombotic therapy. Nonetheless, it remains unclear whether individual components that constitute CHA2 DS2 -VASc score contribute equally to the ischemic stroke risk, particularly in patients with CHA2 DS2 -VASc score of 1. The objective was to describe and compare the risk of ischemic stroke of the six individual components constituting CHA2 DS2 -VASc among AF patients with CHA2 DS2 -VASc score of 1. METHODS AND RESULTS: We studied all patients with CHA2 DS2 -VASc score of 1 and no antithrombotic therapy from our cohort of 9,727 Chinese AF patients. A total of 548 patients were studied: 190 patients with CHA2 DS2 -VASc score of 0 and 358 patients with CHA2 DS2 -VASc score of 1. Of those with a baseline CHA2 DS2 -VASc score of 1, 51.1% patients aged 65-75; 29.3% patients were female; 12.0% had hypertension; 4.5% had heart failure; 2.5% had diabetes; and 0.6% had vascular disease. After 1,758 patient-years of follow-up, the annual incidence of stroke was 2.4% and 6.6% for patients with CHA2 DS2 -VASc score of 0 and 1, respectively. Compared with patients with CHA2 DS2 -VASc score of 0, patients with hypertension leading to CHA2 DS2 -VASc score of 1 were at the highest risk of stroke (Hazard ratio [HR]: 9.8, 95% confidence interval [CI]: 2.7-35.6), followed by patients aged 65-74 (HR: 3.9, 95% CI: 2.3-6.6) and female gender (HR: 2.3, 95% CI: 1.1-4.8). Heart failure, diabetes mellitus, and vascular disease were not associated with stroke. CONCLUSION: In AF patients with CHA2 DS2 -VASc score of 1, hypertension confers the highest risk for stroke among other risk factors comprising the score. A more aggressive thromboprophylaxis strategy may be justified among AF patients with CHA2 DS2 -VASc score of 1 due to hypertension.