title: Correlates and outcomes of warfarin initiation in kidney transplant recipients newly diagnosed with atrial fibrillation.
abstract: In the kidney transplant population with atrial fibrillation (AF), evidence regarding the effectiveness and safety of warfarin treatment is lacking. We used fee-for-service Medicare claims to identify kidney transplant recipients with newly diagnosed AF from the United States Renal Data System. Warfarin use within 30 days of AF diagnosis was ascertained from Medicare Part D prescription claims (2007-11) or using a validated algorithm (1997-2011). The study end points were (i) the composite of death, stroke or gastrointestinal bleed, (ii) death and (iii) death-censored graft failure. Warfarin user and non-user groups were balanced using inverse probability of treatment weighting and hazard ratios were (HRs) estimated using Cox regression. Among 718 subjects with an indication for anticoagulation, 24% initiated warfarin treatment within 30 days of AF diagnosis. Age was the only independent correlate of warfarin use [odds ratio = 1.02 per year; 95% confidence interval (95% CI) 1.01-1.04]. In the larger cohort of 6492 patients with AF, warfarin use [(23.5%) versus non-use (76.5%)] was associated with small and non-significant reductions in the composite of death, stroke or gastrointestinal bleed (HR = 0.92; 95% CI 0.83-1.02), death (HR = 0.92; 95% CI 0.82-1.02) and death-censored graft failure (HR = 0.90; 95% CI 0.76-1.08). Our study suggests the need for clinical trials of warfarin use in the kidney transplant population with AF.
authors.affiliation: Divisions of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA.
authors.forename: Colin R
authors.initials: CR
authors.lastname: Lenihan
authors.affiliation: Divisions of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Montez-Rath
authors.affiliation: Divisions of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA.
authors.forename: Jenny I
authors.initials: JI
authors.lastname: Shen
authors.affiliation: Divisions of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Scandling
authors.affiliation: Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Palo Alto, CA, USA Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
authors.forename: Mintu P
authors.initials: MP
authors.lastname: Turakhia
authors.affiliation: Divisions of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA.
authors.forename: Tara I
authors.initials: TI
authors.lastname: Chang
authors.affiliation: Divisions of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Wolfgang C
authors.initials: WC
authors.lastname: Winkelmayer
mesh_terms: D000368:Aged; D000465:Algorithms; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007674:Kidney Diseases / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D018570:Risk Assessment; D066027:Transplant Recipients; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: anticoagulation; arrhythmia; end-stage renal disease; outcomes; risk assessment