title: Sex difference in appropriate shocks but not mortality during long-term follow-up in patients with implantable cardioverter-defibrillators.
abstract: OBJECTIVE
  Implantable cardioverter-defibrillators (ICDs) have been shown to improve survival, although a considerable number of patients never receive therapy. Implantable cardioverter-defibrillators are routinely implanted regardless of sex. There is continuing controversy whether major outcomes differ between men and women.
  
  
  RESULTS
  In this retrospective single-centre study, 1151 consecutive patients (19% women) undergoing ICD implantation between 1998 and 2010 were followed for mortality and first appropriate ICD shock over 4.9 ± 2.7 years. Sex-related differences were investigated using multivariable Cox models adjusting for potential confounders. During follow-up, 318 patients died, a rate of 5.9% per year among men and 4.6% among women (uncorrected P = 0.08); 266 patients received a first appropriate ICD shock (6.3% per year among men vs. 3.6% among women, P = 0.002). After multivariate correction, independent predictors of all-cause mortality were age (hazard ratio, HR = 1.04 per year of age, 95% confidence interval (CI) [1.03-1.06], P < 0.001), left ventricular ejection fraction (HR = 0.98 per %, 95% CI [0.97-1.00], P = 0.025), renal function (HR = 0.99 per mL/min/1.73 m(2), 95% CI [0.99-1.00], P = 0.009), use of diuretics (HR = 1.81, 95% CI [1.29-2.54], P = 0.0023), peripheral arterial disease (HR = 2.21, 95% CI [1.62-3.00], P < 0.001), and chronic obstructive pulmonary disease (HR = 1.48, 95% CI [1.13-1.94], P = 0.029), but not sex. Female sex (HR = 0.51, 95% CI [0.33-0.81], P = 0.013), older age (HR = 0.98, 95% CI [0.97-0.99], P < 0.001), and primary prophylactic ICD indication (HR = 0.69, 95% CI [0.52-0.93], P = 0.043) were independent predictors for less appropriate shocks.
  
  
  CONCLUSIONS
  Women receive 50% less appropriate shocks than men having similar mortality in this large single-centre population. These data may pertain to individually improved selection of defibrillator candidates using risk factors, e.g. sex as demonstrated in this study.
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Seegers
authors.affiliation: Department of Medicine, University Hospital, Basel, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Conen
authors.affiliation: Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Jung
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany.
authors.forename: Leonard
authors.initials: L
authors.lastname: Bergau
authors.affiliation: Department of Medicine, Cardiology Division, Charité Campus Virchow Klinikum, Berlin, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Dorenkamp
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Lüthje
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Sohns
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Sossalla
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Fischer
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hasenfuss
authors.affiliation: Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Friede
authors.affiliation: Department of Cardiology and Pneumology, University Medical Center Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany markus.zabel@med.uni-goettingen.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Zabel
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000628:therapy*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D005260:Female; D005500:Follow-Up Studies; D005858:Germany; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors
keywords: Cardiovascular mortality; Implantable cardioverter-defibrillator; Risk factors; Sex difference; Sudden cardiac death