title: The prognosis of implantable defibrillator patients treated with cardiac resynchronization therapy: comorbidity burden as predictor of mortality.
abstract: OBJECTIVE
  Comorbidity, such as myocardial infarction, diabetes, and renal failure, plays a pivotal role in the prognosis of a patient with arrhythmias. However, data on the prognostic impact of comorbiditiy in heart failure patients with cardiac resynchronization therapy and defibrillation (CRT-D) are scarce. The purpose of this study was to determine the impact of comorbidity on survival in CRT-D patients.
  
  
  RESULTS
  The study population consisted of 463 heart failure patients who received a CRT-D between 1999 and 2008 in Rotterdam and Basel. The Charlson comorbidity index (CCI) is often used as an adjusting variable in prognostic models. The Cox proportional hazards analysis was performed to determine the independent effect of comorbidity on survival. During a median follow-up of 30.5 months, 85 patients died. Mortality rates at 1 and 7 years were 6.3 and 32.3%. Cumulative incidence of implantable cardioverter defibrillator (ICD) therapy at 7 years was 50%, and death without ICD therapy was observed in 9% of patients. At least three comorbid conditions were observed in 81% of patients. Patients who died had a higher CCI score compared with those who survived (3.9 ± 1.5 vs. 2.9 ± 1.5; P < 0.001). An age-adjusted CCI score ≥ 5 was a predictor of mortality (hazard ratio 3.69, 95% CI 2.06-6.60; P < 0.001) independent from indication for ICD therapy, and from ICD interventions during the clinical course.
  
  
  CONCLUSIONS
  Comorbidity is often present in heart failure patients, and a high comorbidity burden was a significant predictor of mortality in CRT-D recipients. Comorbidity cannot predict appropriate ICD therapy. Death without prior ICD therapy occurs in a minor proportion of patients.
authors.affiliation: Department of Cardiology, Erasmus MC, Rotterdam, the Netherlands. d.theuns@erasmusmc.nl
authors.forename: Dominic A M J
authors.initials: DA
authors.lastname: Theuns
authors.forename: Beat A
authors.initials: BA
authors.lastname: Schaer
authors.forename: Osama I I
authors.initials: OI
authors.lastname: Soliman
authors.forename: David
authors.initials: D
authors.lastname: Altmann
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Marcel L
authors.initials: ML
authors.lastname: Geleijnse
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.forename: Luc
authors.initials: L
authors.lastname: Jordaens
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D015897:Comorbidity; D017147:Defibrillators, Implantable; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D051437:Renal Insufficiency / Q000453:epidemiology; D012189:Retrospective Studies; D015996:Survival Rate