title: Time Trends of Aspirin and Warfarin Use on Stroke and Bleeding Events in Chinese Patients With New-Onset Atrial Fibrillation.
abstract: BACKGROUND
  Much of the clinical epidemiology and treatment patterns for patients with atrial fibrillation (AF) are derived from Western populations. Limited data are available on antithrombotic therapy use over time and its impact on the stroke or bleeding events in newly diagnosed Chinese patients with AF. The present study investigates time trends in warfarin and aspirin use in China in relation to stroke and bleeding events in a Chinese population.
  
  
  METHODS
  We used a medical insurance database involving > 10 million individuals for the years 2001 to 2012 in Yunnan, a southwestern province of China, and performed time-trend analysis on those with newly diagnosed AF. Cox proportional hazards time-varying exposures were used to determine the risk of stroke or bleeding events associated with antithrombotic therapy among patients with AF.
  
  
  RESULTS
  Among the randomly sampled 471,446 participants, there were 1,237 patients with AF, including 921 newly diagnosed with AF, thus providing 4,859 person-years of experience (62% men; mean attained age, 70 years). The overall rate of antithrombotic therapy was 37.7% (347 of 921 patients), with 4.1% (38 of 921) on warfarin and 32.3% (298 of 921) on aspirin. Antithrombotic therapy was not related to stroke/bleeding risk scores (CHADS2 [congestive heart failure, hypertension, age ≥ 75 years, diabetes, stroke (doubled)] score, P = .522; CHA2DS2-VASc [congestive heart failure, hypertension, age ≥ 75 years (doubled), diabetes mellitus, stroke or transient ischemic attack (doubled), vascular disease, age 65 to 74 years, and female sex] score, P = .957; HAS-BLED [hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly (> 65 years), drugs/alcohol concomitantly] score, P = .095). The use of antithrombotic drugs (mainly aspirin) increased in both women and men over time, with the rate of aspirin increasing from 4.0% in 2007 to 46.1% in 2012 in the former, and from 7.7% in 2007 to 61.9% in 2012 in the latter (P for trend for both, < .005). In the overall cohort, the annual stroke rate was approximately 6% and the annual major bleeding rate was about 1%. Compared with nonantithrombotic therapy, the hazard ratio for ischemic stroke was 0.68 (95% CI, 0.39-1.18) for aspirin and 1.39 (0.54-3.59) for warfarin.
  
  
  CONCLUSIONS
  Aspirin use increased among Chinese patients newly diagnosed with AF, with no relationship to the patient's stroke or bleeding risk. Warfarin use was very low. Given the health-care burden of AF and its complications, our study has major implications for health-care systems in non-Western countries, given the global burden of this common arrhythmia.
authors.affiliation: Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yutao
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China; Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Gerontology (Drs Tian and Lip), Second People's Hospital, Yunnan Province, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yutang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Gerontology (Drs Tian and Lip), Second People's Hospital, Yunnan Province, China; University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, England; Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Faculty of Health, Aalborg University, Aalborg, Denmark. Electronic address: g.y.h.lip@bham.ac.uk.
authors.forename: Gregory Y H
authors.initials: GYH
authors.lastname: Lip
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D001241:Aspirin / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006470:Hemorrhage / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012737:Sex Factors; D020521:Stroke / Q000453:epidemiology* / Q000517:prevention & control; D013997:Time Factors; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D005343:Fibrinolytic Agents; D014859:Warfarin; D001241:Aspirin