title: Absence of Oral Anticoagulation and Subsequent Outcomes Among Outpatients with Atrial Fibrillation.
abstract: BACKGROUND
  Prior studies have shown a treatment gap in oral anticoagulation (OAC) use among patients with atrial fibrillation yet have incompletely characterized factors associated with failure to treat and subsequent outcomes in contemporary practice.
  
  
  METHODS
  Using data collected between June 2010 and August 2011 from 174 ambulatory care sites in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, we identified factors associated with absence of OAC via stratified logistic regression. Using weighted Cox regression, we assessed the association between OAC non-use and subsequent outcomes over 2.5 years.
  
  
  RESULTS
  Among 9553 patients, 2202 (23.0%) were not on OAC. Among OAC nonrecipients, 1846 (83.8%) had a CHA2DS2-VASc score ≥2. Factors independently associated with OAC non-use included atrial fibrillation type (paroxysmal odds ratio [OR] 0.73, 95% confidence interval [CI] 0.54-0.99; persistent OR 0.14, 95% CI 0.10-0.21; permanent OR 0.35, 95% CI 0.25-0.49; reference = new-onset), left atrial diameter enlargement (mild OR 0.80, 95% CI 0.66-0.97; moderate 0.58, 95% CI 0.47-0.73; severe 0.53, 95% CI 0.42-0.68; reference = normal diameter), and age >80 years (OR 1.04, 95% CI 1.02-1.08). Untreated patients had a higher risk of death (adjusted hazard ratio [HR] 1.22, 95% CI 1.05-1.41), a lower bleeding risk (adjusted HR 0.35, 95% CI 0.15-0.81), and a nonsignificant trend toward higher risk of stroke/non-central nervous system embolism/transient ischemic attack than those treated (adjusted HR 1.18, 95% CI 0.91-1.54).
  
  
  CONCLUSIONS
  A majority of atrial fibrillation patients not treated with an OAC in current community practice meet guideline indications for treatment. Atrial fibrillation burden, chronicity, and comorbidity are associated with nontreatment. Untreated patients are at increased risk for adverse outcomes.
authors.affiliation: Cardiology Section, VA Eastern Colorado and Health Care System, Denver; Department of Medicine, University of Colorado Anschutz Medical Campus, School of Medicine, Aurora. Electronic address: paul.hess@ucdenver.edu.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Hess
authors.affiliation: Duke Clinical Research Institute, Durham, NC.
authors.forename: Sunghee
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Medicine, University of California, Los Angeles.
authors.forename: Gregg C
authors.initials: GC
authors.lastname: Fonarow
authors.affiliation: Duke Clinical Research Institute, Durham, NC.
authors.forename: Laine
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Harvard Medical School and Massachusetts General Hospital, Boston.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Singer
authors.affiliation: Department of Medicine, Yale University School of Medicine, New Haven, Conn.
authors.forename: James V
authors.initials: JV
authors.lastname: Freeman
authors.affiliation: Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minn.
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Gersh
authors.affiliation: Department of Medicine, New York School of Medicine, Lenox Hill Hospital.
authors.forename: Jack
authors.initials: J
authors.lastname: Ansell
authors.affiliation: Lankenau Institute for Medical Research, Wynnewood, Penn.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Kowey
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Palo Alto, Calif.
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Mahaffey
authors.affiliation: Department of Cardiovascular Research, St. Luke's Mid America Heart Institute, Kansas City, Mo; Department of Medicine, University of Missouri-Kansas City.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Chan
authors.affiliation: Duke Clinical Research Institute, Durham, NC; University of Utah, Salt Lake City.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Steinberg
authors.affiliation: Duke Clinical Research Institute, Durham, NC.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Peterson
authors.affiliation: Duke Clinical Research Institute, Durham, NC.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Piccini
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000379:methods; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications* / Q000188:drug therapy / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012720:Severity of Illness Index
chemical_list: D000925:Anticoagulants
keywords: Atrial fibrillation; Oral anticoagulation; Outcomes; Quality of care