title: Risk of stroke and intracranial hemorrhage in 9727 Chinese with atrial fibrillation in Hong Kong.
abstract: BACKGROUND
  Current risk schemes to predict ischemic stroke and intracranial hemorrhage (ICH) in atrial fibrillation (AF) are derived primarily using a Caucasian population.
  
  
  OBJECTIVE
  The purpose of this study was to describe the risk of ischemic stroke and ICH in a large contemporary "real world" cohort of Chinese AF patients in Hong Kong with detailed long-term follow-up.
  
  
  METHODS
  This observational study used a hospital-based cohort of Chinese patients with nonvalvular AF.
  
  
  RESULTS
  Among 9727 patients with nonvalvular AF (age 76.9 ± 12.5 years, 52.1% female), 3881 patients (39.9%) did not receive antithrombotic therapy, 3934 patients (40.4%) were taking aspirin, and 1912 (19.7%) were taking warfarin. After mean follow-up of 3.19 years, 847 patients (21.8%) without antithrombotic therapy developed ischemic strokes (annual risk 9.28%, 95% confidence interval [CI] 8.89%-9.70%). There was a progressively increase in annual risk of ischemic stroke with increasing CHADS2 and CHA2DS2VASc scores. The c-statistics revealed that CHA2DS2-VASc scores (0.525, 95% CI 0.509-0.541, P = .017) was better than CHADS2 scores (0.506, 95% CI 0.490-0.522, P = .584) in predicting ischemic stroke. Use of aspirin and of warfarin were associated with reduced annual risk of ischemic stroke by 18.7% and 52.7%, respectively (P <.05). The annual incidence of ICH in patients taking aspirin and warfarin was 0.77% per year and 0.80% per year, respectively. The adjusted net clinical benefit favored warfarin over aspirin or no therapy for almost all Chinese AF patients CHA2DS2-VASc score ≥1.
  
  
  CONCLUSIONS
  Chinese AF patients are at high risk for ischemic stroke. Analysis of the net clinical benefit favors the use of warfarin over aspirin or no therapy for stroke prevention in a broad range of Chinese AF patients.
authors.affiliation: Cardiology Division, Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR, China. Electronic address: cwdsiu@hku.hk.
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
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: Department of Statistics and Actuarial Science, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Kwok-Fai
authors.initials: KF
authors.lastname: Lam
authors.affiliation: Cardiology Division, Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications*; D002545:Brain Ischemia / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D020300:Intracranial Hemorrhages / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D000925:Anticoagulants
keywords: Atrial fibrillation; CHA(2)DS-VASc score; CHADS(2) score; Intracranial hemorrhage; Ischemic stroke