title: Age Threshold for Increased Stroke Risk Among Patients With Atrial Fibrillation: A Nationwide Cohort Study From Taiwan.
abstract: 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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Division 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.
authors.forename: Tze-Fan
authors.initials: TF
authors.lastname: Chao
authors.affiliation: Division 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; General Clinical Research Center, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Kang-Ling
authors.initials: KL
authors.lastname: Wang
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Public Health and School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
authors.affiliation: Division 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.
authors.forename: Yenn-Jiang
authors.initials: YJ
authors.lastname: Lin
authors.affiliation: Division 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.
authors.forename: Shih-Lin
authors.initials: SL
authors.lastname: Chang
authors.affiliation: Division 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.
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Lo
authors.affiliation: Division 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.
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Hu
authors.affiliation: Division 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.
authors.forename: Ta-Chuan
authors.initials: TC
authors.lastname: Tuan
authors.affiliation: Division 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.
authors.forename: Fa-Po
authors.initials: FP
authors.lastname: Chung
authors.affiliation: Division 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.
authors.forename: Jo-Nan
authors.initials: JN
authors.lastname: Liao
authors.affiliation: Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Tzeng-Ji
authors.initials: TJ
authors.lastname: Chen
authors.affiliation: Division 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; General Clinical Research Center, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chern-En
authors.initials: CE
authors.lastname: Chiang
authors.affiliation: University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, United Kingdom.
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
authors.affiliation: Division 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. Electronic address: epsachen@ms41.hinet.net.
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000328:Adult; D000367:Age Factors; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D020521:Stroke / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D013624:Taiwan / Q000453:epidemiology
chemical_list: D000925:Anticoagulants
keywords: CHA(2)DS(2)-VASc score; Taiwan; ischemic stroke; risk assessment