title: Variation in use of dual-chamber implantable cardioverter-defibrillators: results from the national cardiovascular data registry.
abstract: BACKGROUND
  Among patients without an indication for a pacemaker, current evidence is inconclusive whether a dual-chamber implantable cardioverter-defibrillator (ICD) is superior to a single-chamber ICD. The current use of dual-chamber ICDs is not well characterized.
  
  
  METHODS
  We conducted a cross-sectional study exploring hospital-level variation in the use of dual-chamber ICDs across the United States. Patients receiving a primary prevention ICD from 2006 through 2009 without a documented indication for a pacemaker were included. Multivariate hierarchical logistic regression was used to explore patient, health care provider, and physician factors related to the use of a dual-chamber device.
  
  
  RESULTS
  Dual-chamber devices were implanted in 58% of the 87,115 patients without a pacing indication among 1293 hospitals, with hospital rates ranging from 0% in 33 centers to 100% in 109 centers. In multivariate analysis, geographic region was a strong independent predictor of dual-chamber device use, ranging from 36.4% in New England (reference region) to 66.4% in the Pacific region (odds ratio [OR], 5.25; 95% CI, 3.35-8.21). Hospital clustering was assessed using a median OR which was 3.96, meaning that 2 identical patients at different hospitals would have nearly a 4-fold difference in their chance of receiving a dual-chamber ICD.
  
  
  CONCLUSIONS
  Use of dual-chamber ICDs for the primary prevention of sudden cardiac death among patients without an indication for permanent pacing varies markedly at the hospital level in the United States. This is a clear example of how practice can vary independent of patient factors.
authors.affiliation: Department of Medicine, University of Colorado Denver School of Medicine, Aurora, 80045, USA. daniel.matlock@ucdenver.edu
authors.forename: Dan D
authors.initials: DD
authors.lastname: Matlock
authors.forename: Pamela N
authors.initials: PN
authors.lastname: Peterson
authors.forename: Yongfei
authors.initials: Y
authors.lastname: Wang
authors.forename: Jeptha P
authors.initials: JP
authors.lastname: Curtis
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Reynolds
authors.forename: Paul D
authors.initials: PD
authors.lastname: Varosy
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Masoudi
mesh_terms: D000368:Aged; D016000:Cluster Analysis; D015897:Comorbidity; D003430:Cross-Sectional Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000208:ethnology / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004867:Equipment Design; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009511:New England / Q000453:epidemiology; D016017:Odds Ratio; D010138:Pacemaker, Artificial; D019601:Pacific States / Q000453:epidemiology; D011237:Predictive Value of Tests; D011322:Primary Prevention / Q000379:methods; D012042:Registries