Age Threshold for Increased Stroke Risk among Patients with Atrial Fibrillation A Nationwide Cohort Study from Taiwan

Tze Fan Chao, Kang Ling Wang, Chia Jen Liu, Yenn Jiang Lin, Shih Lin Chang, Li Wei Lo, Yu Feng Hu, Ta Chuan Tuan, Fa Po Chung, Jo Nan Liao, Tzeng Ji Chen, Chern En Chiang, Gregory Y.H. Lip, Shih Ann Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

102 Scopus citations


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.

Original languageEnglish
Pages (from-to)1339-1347
Number of pages9
JournalJournal of the American College of Cardiology
Issue number12
StatePublished - 22 Sep 2015


  • Key Words CHADS-VASc score
  • Taiwan
  • ischemic stroke
  • risk assessment


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