title: Continued Use of Warfarin in Veterans with Atrial Fibrillation After Dementia Diagnosis.
abstract: OBJECTIVE
  To determine the effectiveness of warfarin in older adults with dementia.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Department of Veterans Affairs national healthcare system.
  
  
  METHODS
  Veterans aged 65 and older (73% aged ≥75, 99% male, 91% white) who had been receiving warfarin for nonvalvular atrial fibrillation for at least 6 months, were newly diagnosed with dementia in fiscal year 2007 or 2008, and were not enrolled in Medicare Advantage (n = 2,572).
  
  
  METHODS
  The onset of dementia was defined according to International Classification of Diseases, Ninth Revision, code. Participants were followed for up to 4 years for persistence of warfarin therapy, anticoagulation control, major hemorrhage, ischemic stroke, and all-cause mortality.
  
  
  RESULTS
  The average CHADS2 score was 3.3 ± 1.3. After a diagnosis of dementia, 405 individuals (16%) persisted on warfarin therapy. Unadjusted Cox proportional hazards analysis demonstrated a protective effect of warfarin in prevention of ischemic stroke (hazard ratio (HR) = 0.64, 95% confidence interval (CI) = 0.46-0.89, P = .008), major bleeding (HR = 0.72, 95% CI = 0.55-0.94, P = .02), and all-cause mortality (HR = 0.66, 95% CI = 0.55-0.79, P < .001). Using propensity score matching, the protective effect of continuing warfarin persisted in prevention of stroke (HR = 0.74, 95% CI = 0.54-0.996, P = .047) and mortality (HR = 0.72, 95% CI = 0.60-0.87, P < .001), with no statistically significant decrease in risk of major bleeding (HR = 0.78, 95% CI = 0.61-1.01, P = .06).
  
  
  CONCLUSIONS
  Discontinuing warfarin after a diagnosis of dementia is associated with a significant increase in stroke and mortality.
authors.affiliation: Geriatric Research, Education, and Clinical Center (GRECC), Veterans Affairs Boston Healthcare System, Boston, Massachusetts.|Division of Aging, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ariela R
authors.initials: AR
authors.lastname: Orkaby
authors.affiliation: Center for Patient Safety and Quality Research, Boston Children's Hospital, Boston, Massachusetts.|Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
authors.forename: Al
authors.initials: A
authors.lastname: Ozonoff
authors.affiliation: Center for Healthcare Organization and Implementation Research, Bedford Veterans Affairs Medical Center, Bedford, Massachusetts.
authors.forename: Joel I
authors.initials: JI
authors.lastname: Reisman
authors.affiliation: Center for Healthcare Organization and Implementation Research, Bedford Veterans Affairs Medical Center, Bedford, Massachusetts.|School of Public Health, Boston University, Boston, Massachusetts.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Miller
authors.affiliation: Center for Healthcare Organization and Implementation Research, Bedford Veterans Affairs Medical Center, Bedford, Massachusetts.
authors.forename: Shibei
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Center for Healthcare Organization and Implementation Research, Bedford Veterans Affairs Medical Center, Bedford, Massachusetts.|Department of Medicine, Section of Internal Medicine, Boston University Medical Center, Boston, Massachusetts.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Rose
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D057216:Propensity Score; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D020521:Stroke / Q000517:prevention & control*; D014481:United States / Q000453:epidemiology; D014728:Veterans; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: atrial fibrillation; dementia; warfarin