title: Evaluation of the Charlson comorbidity index to predict early mortality in implantable cardioverter defibrillator patients.
abstract: BACKGROUND
  Current guidelines consider the implantation of an implantable cardioverter defibrillator (ICD) a class III indication in patients with a life expectancy of <1 year. An evaluation of concomitant noncardiac conditions may identify patients whom may not derive benefit with ICD therapy. We sought to evaluate the association of the Charlson comorbidity index (CCI) on the prediction of early mortality (EM), death <1 year after ICD implant.
  
  
  METHODS
  The study population consisted of patients (n = 1062) undergoing ICD implantation for the primary or secondary prevention of sudden cardiac death from 1997 to 2007. The predictive value of the CCI on the risk of EM and appropriate shock therapy for ventricular arrhythmias as compared to patients without EM after ICD implant was calculated using multivariable Cox proportional hazards and receiver operator analyses.
  
  
  RESULTS
  Patients experiencing EM (n = 110) demonstrated higher CCI scores (mean 2.8 ± 1.3 vs 1.5 ± 1.2, P < 0.001) as compared to individuals without EM (n = 963). Among patients with a CCI of 0, 1, 2, 3, 4, and ≥5, the incidence of EM increased from 5% to 78%. The CCI was an independent predictor of EM (AHR 1.4 [95% CI 1.2-1.6], P < 0.001, per single score increase). Patients who experienced EM demonstrated a decreased incidence of appropriate ICD therapy when compared to patients without EM (AHR 0.4 [95% CI 0.2-0.7], P = 0.001).
  
  
  CONCLUSIONS
  Noncardiac conditions are commonly observed among patients undergoing ICD implantation. Guidelines must incorporate a comprehensive assessment of concomitant comorbidities to minimize the risk of EM and to maximize the survival benefit with ICD therapy.
authors.affiliation: Division of Cardiology, Section of Heart Rhythm Management and the Evidence Based Practice Center, Hartford Hospital, Hartford CT, USA.
authors.forename: Sanjeev P
authors.initials: SP
authors.lastname: Bhavnani
authors.forename: Craig I
authors.initials: CI
authors.lastname: Coleman
authors.forename: Danette
authors.initials: D
authors.lastname: Guertin
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Yarlagadda
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Clyne
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kluger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D002423:Cause of Death; D015331:Cohort Studies; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000401:mortality*; D005260:Female; D006329:Heart Conduction System / Q000002:abnormalities; D006801:Humans; D053208:Kaplan-Meier Estimate; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011322:Primary Prevention / Q000379:methods; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome
keywords: comorbidities; implantable cardioverter defibrillator; mortality; outcomes; risk stratification; shocks