title: Significant underuse of warfarin in patients with nonvalvular atrial fibrillation: results from the China national stroke registry.
abstract: BACKGROUND
  Warfarin reduces the risk of stroke in patients with atrial fibrillation (AF) but is often underused in clinical practice. We aimed to examine the current state of warfarin use in nonvalvular atrial fibrillation (NVAF) patients with first-ever ischemic stroke (IS) or transient ischemic attack (TIA) in China and to analysis factors causing such underuse.
  
  
  METHODS
  By accessing the China National Stroke Registry, data on consecutive patients with known NVAF who developed first-ever IS or TIA were studied. Proportion of warfarin use was estimated in those patients with known NVAF who should be eligible for anticoagulation therapy. Factors associated with warfarin underuse were identified by multivariate logistic regression.
  
  
  RESULTS
  Of 11,080 patients with first-ever IS or TIA, 996 (9.7%) had NVAF and no contraindications to anticoagulation therapy and 592 of them had history of AF. Among these patients, only 96 (16.2%) were on warfarin and 496 (83.8%) were not. In those patients on warfarin, only 1 of his international normalized ratios on admission was in the therapeutic range of 2.0-3.0. Based on the CHADS2 scores, about 20.2% low-risk AF patients took warfarin; however, only 15.2% moderate and 16.4% high-risk patients were on warfarin. Older patients and patients with history of coronary heart disease (CHD) were less likely to be given warfarin, whereas patients with history of prestroke antiplatelet use were more likely to take warfarin.
  
  
  CONCLUSIONS
  We found that warfarin was significantly underused in patients with known NVAF in China. Age and CHD and prestroke antiplatelet therapy were related factors.
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Chunjuan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Chunxue
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Yilong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Xingquan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Liu
authors.affiliation: INI Stroke Center and Stroke Network, OSF Healthcare System, University of Illinois College of Medicine, Peoria, Illinois.
authors.forename: David Z
authors.initials: DZ
authors.lastname: Wang
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China. Electronic address: yongjunwang1962@gmail.com.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D002545:Brain Ischemia / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D003327:Coronary Disease / Q000453:epidemiology; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D019934:International Normalized Ratio; D002546:Ischemic Attack, Transient / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians'; D012042:Registries; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016896:Treatment Outcome; D014859:Warfarin / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin
keywords: Anticoagulation; atrial fibrillation; stroke management; transient ischemic attack; warfarin