CHA2DS2-VASc Recalibration With an Additional Age Category (50-64 Years) Enhances Stroke Risk Stratification in Chinese Patients With Atrial Fibrillation

Abstract

Background: Chinese patients with atrial fibrillation (AF) and a low CHA₂DS₂-VASc have a disproportionately high ischemic stroke risk; nonetheless, little is known about the impact of age on ischemic stroke risk in this population. In this study, we aimed to examine the age-related ischemic stroke risk in Chinese patients with nonvalvular AF without other risk factors for stroke.

Methods: This was a hospital-based observational registry.

Results: A total of 1198 Chinese patients with AF (mean age, 73.6 ± 16.5 years; male sex, 53.3%) were included in this analysis. The mean CHA₂DS₂-VASc and HAS-BLED score were 1.81 ± 1.00 and 1.32 ± 0.77, respectively, and none of the patients was prescribed antiplatelet or anticoagulation therapy. After a mean follow-up of 2.95 years, there were 234 ischemic strokes (19.5%), with an annual ischemic stroke incidence of 6.62%/y. The overall annual ischemic stroke risk was 0.43%/y, 5.87%/y, 7.49%/y, and 8.04%/y for age groups < 50 years, 50-64 years, 65-74 years, and ≥ 75 years, respectively. There was a 10- to 20-fold gradient in ischemic stroke risk that increased sharply after the age of 50 years. The hazard ratios were 1.0, 13.0, 19.3, and 21.6 for age groups < 50 years, 50-64 years, 65-74 years and ≥ 75 years, respectively (P for trend < 0.0001). Similar trends were also observed in both male and female patients with AF.

Conclusions: Chinese patients with AF and a low CHA₂DS₂-VASc were at a disproportionally high risk of ischemic stroke. Chinese patients between 50 and 64 years have a high risk for stroke despite a low CHA₂DS₂-VASc and a low bleeding risk. Only patients aged < 50 years have a truly low risk.