title: Outcomes After Warfarin Initiation in a Cohort of Hemodialysis Patients With Newly Diagnosed Atrial Fibrillation.
abstract: BACKGROUND
  Although warfarin is indicated to prevent ischemic strokes in most patients with atrial fibrillation (AF), evidence supporting its use in hemodialysis patients is limited. Our aim was to examine outcomes after warfarin therapy initiation, relative to no warfarin use, following incident AF in a large cohort of hemodialysis patients who had comprehensive prescription drug coverage through Medicare Part D.
  
  
  METHODS
  Retrospective observational cohort study.
  
  
  METHODS
  Patients in the US Renal Data System undergoing maintenance hemodialysis who had AF newly diagnosed in 2007 to 2011, with Medicare Part D coverage, who had no recorded history of warfarin use.
  
  
  METHODS
  Warfarin therapy initiation, identified by a filled prescription within 30 days of the AF event.
  
  
  RESULTS
  Death, ischemic stroke, hemorrhagic stroke, severe gastrointestinal bleeding, and composite outcomes.
  
  
  METHODS
  HRs estimated by applying Cox regression to an inverse probability of treatment and censoring-weighted cohort.
  
  
  RESULTS
  Of 12,284 patients with newly diagnosed AF, 1,838 (15%) initiated warfarin therapy within 30 days; however, ∼70% discontinued its use within 1 year. In intention-to-treat analyses, warfarin use was marginally associated with a reduced risk of ischemic stroke (HR, 0.68; 95% CI, 0.47-0.99), but not with the other outcomes. In as-treated analyses, warfarin use was associated with reduced mortality (HR, 0.84; 95% CI, 0.73-0.97).
  
  
  CONCLUSIONS
  Short observation period, limited number of nonfatal events, limited generalizability of results to more affluent patients.
  
  
  CONCLUSIONS
  In hemodialysis patients with incident AF, warfarin use was marginally associated with reduced risk of ischemic stroke, and there was a signal toward reduced mortality in as-treated analyses. These results support clinical equipoise regarding the use of warfarin in hemodialysis patients and underscore the need for randomized trials to fill this evidence gap.
authors.affiliation: Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto, CA; Division of Nephrology and Hypertension, Harbor-UCLA Medical Center, Torrance, CA.
authors.forename: Jenny I
authors.initials: JI
authors.lastname: Shen
authors.affiliation: Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto, CA.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Montez-Rath
authors.affiliation: Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto, CA.
authors.forename: Colin R
authors.initials: CR
authors.lastname: Lenihan
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, Palo Alto, CA; Veterans Affairs Palo Alto Health Care System, Stanford University School of Medicine, Palo Alto, CA.
authors.forename: Mintu P
authors.initials: MP
authors.lastname: Turakhia
authors.affiliation: Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, TX.
authors.forename: Tara I
authors.initials: TI
authors.lastname: Chang
authors.affiliation: Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto, CA; Division of Cardiovascular Medicine, Department of Medicine, Palo Alto, CA. Electronic address: wolfgang.winkelmayer@bcm.edu.
authors.forename: Wolfgang C
authors.initials: WC
authors.lastname: Winkelmayer
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality*; D002423:Cause of Death; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000379:methods / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment; D020521:Stroke / Q000401:mortality / Q000517:prevention & control; D015996:Survival Rate; D016896:Treatment Outcome; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Dialysis; atrial fibrillation (AF); bleeding; cardiac arrhythmia; drug safety; end-stage renal disease (ESRD); hemodialysis; hemorrhagic stroke; ischemic stroke; mortality; oral anticoagulation; prevention; warfarin