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Computerized Adaptive Testing System of Functional Assessment of Stroke
Published on: January 7, 2019
Age Threshold for Increased Stroke Risk Among Patients With Atrial Fibrillation: A Nationwide Cohort Study From
Tze-Fan Chao1, Kang-Ling Wang2, Chia-Jen Liu3
1Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan.
Background:
Recent studies from Asia have suggested that the risk of ischemic stroke for patients with atrial fibrillation (AF) with a "low-risk" congestive heart failure, hypertension, age ≥75, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, age 65 to 74, female (CHA2DS2-VASc) score of 0 (for males) or 1 (for females) might be higher than that for non-Asians.
Objectives:
This study hypothesized that the age threshold (65 years) used in the CHA2DS2-VASc system for initiating oral anticoagulants (OACs) might be lower in Taiwanese AF patients than in non-Asians.
Methods:
We used the National Health Insurance Research Database in Taiwan to study 186,570 nonanticoagulated AF patients. There were 9,416 males with a CHA2DS2-VASc score of 0 and 6,390 females with a CHA2DS2-VASc score of 1. Their risk of ischemic stroke was analyzed with stratification on the basis of age.
Results:
The annual risks of ischemic stroke for males (score 0) and females (score 1) were 1.15% and 1.12%, respectively, and continuously increased from younger to older age groups, with an increment in stroke risk evident for patients >50 years of age. At a cutoff of 50 years, patients could be further stratified into 2 subgroups with different stroke risks (>50 years of age: 1.78%/year; vs. <50 years of age: 0.53%/year). This observation was consistent for males (1.95%/year vs. 0.46%/year, respectively) and females (1.58%/year vs. 0.64%/year, respectively) with AF. In a subgroup analysis, the annual risks of ischemic stroke for males and females with AF 50 to 54 years of age were 1.47% and 1.07%, respectively.
Conclusions:
For Taiwanese patients 50 to 64 years of age, the annual stroke risk was 1.78%, which may exceed the threshold for OAC use for stroke prevention. The annual risk of ischemic stroke for AF patients <50 years of age was 0.53%, which was truly low-risk, and OACs could be omitted. Whether resetting the age threshold to 50 years could refine current clinical risk stratification for Asian AF patients deserves further study.
