title: Survival of patients receiving a primary prevention implantable cardioverter-defibrillator in clinical practice vs clinical trials.
abstract: OBJECTIVE
  Randomized clinical trials have shown that implantable cardioverter-defibrillator (ICD) therapy saves lives. Whether the survival of patients who received an ICD in primary prevention clinical trials differs from that of trial-eligible patients receiving a primary prevention ICD in clinical practice is unknown.
  
  
  OBJECTIVE
  To determine whether trial-eligible patients who received a primary prevention ICD as documented in a large national registry have a survival rate that differs from the survival rate of similar patients who received an ICD in the 2 largest primary prevention clinical trials, MADIT-II (n = 742) and SCD-HeFT (n = 829).
  
  
  METHODS
  Retrospective analysis of data for patients enrolled in the National Cardiovascular Data Registry ICD Registry between January 1, 2006, and December 31, 2007, meeting the MADIT-II criteria (2464 propensity score-matched patients) or the SCD-HeFT criteria (3352 propensity score-matched patients). Mortality data for the registry patients were collected through December 31, 2009.
  
  
  METHODS
  Cox proportional hazards models were used to compare mortality from any cause.
  
  
  RESULTS
  The median follow-up time in MADIT-II, SCD-HeFT, and the ICD Registry was 19.5, 46.1, and 35.2 months, respectively. Compared with patients enrolled in the clinical trials, patients in the ICD Registry were significantly older and had a higher burden of comorbidities. In the matched cohorts, there was no significant difference in survival between MADIT-II-like patients in the registry and MADIT-II patients randomized to receive an ICD (2-year mortality rates: 13.9% and 15.6%, respectively; adjusted ICD Registry vs trial hazard ratio, 1.06; 95% CI, 0.85-1.31; P = .62). Likewise, the survival among SCD-HeFT-like patients in the registry was not significantly different from survival among patients randomized to receive ICD therapy in SCD-HeFT (3-year mortality rates: 17.3% and 17.4%, respectively; adjusted registry vs trial hazard ratio, 1.16; 95% CI, 0.97-1.38; P = .11).
  
  
  CONCLUSIONS
  There was no significant difference in survival between clinical trial patients randomized to receive an ICD and a similar group of clinical registry patients who received a primary prevention ICD. Our findings support the continued use of primary prevention ICDs in similar patients seen in clinical practice.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00000609.
authors.affiliation: Duke Clinical Research Institute, PO Box 17969, Durham, NC 27715, USA. alkha001@mc.duke.edu
authors.forename: Sana M
authors.initials: SM
authors.lastname: Al-Khatib
authors.forename: Anne
authors.initials: A
authors.lastname: Hellkamp
authors.forename: Gust H
authors.initials: GH
authors.lastname: Bardy
authors.forename: Stephen
authors.initials: S
authors.lastname: Hammill
authors.forename: W Jackson
authors.initials: WJ
authors.lastname: Hall
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Mark
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Anstrom
authors.forename: Jeptha
authors.initials: J
authors.lastname: Curtis
authors.forename: Hussein
authors.initials: H
authors.lastname: Al-Khalidi
authors.forename: Lesley H
authors.initials: LH
authors.lastname: Curtis
authors.forename: Paul
authors.initials: P
authors.lastname: Heidenreich
authors.forename: Eric D
authors.initials: ED
authors.lastname: Peterson
authors.forename: Gillian
authors.initials: G
authors.lastname: Sanders
authors.forename: Nancy
authors.initials: N
authors.lastname: Clapp-Channing
authors.forename: Kerry L
authors.initials: KL
authors.lastname: Lee
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
mesh_terms: D000367:Age Factors; D000368:Aged; D002423:Cause of Death; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004608:Eligibility Determination; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention; D057216:Propensity Score; D016032:Randomized Controlled Trials as Topic; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016019:Survival Analysis