Effect of cardiac and noncardiac conditions on survival after defibrillator implantation.
OBJECTIVE
We sought to examine outcomes in recipients of implantable cardioverter-defibrillators (ICDs) and the effect of age, gender, and comorbidities on survival.


BACKGROUND
Age, gender, and comorbidities may significantly affect outcomes in ICD recipients.


METHODS
We examined factors associated with mortality in 2,467 ICD recipients in Ontario, Canada, using a province-wide database. Comorbidities were identified retrospectively by examining all diagnosis codes within the 3 years before implant.


RESULTS
Mean ages at ICD implant were 63.2 +/- 12.5 years (1,944 men) and 59.8 +/- 15.9 years (523 women). Mortality rates at one and 2 years were 7.8% and 14.0%. Older age at implant increased the risk of death with hazard ratios (HR) of 2.05 (95% confidence interval [CI] 1.70 to 2.47) and 3.00 (95% CI 2.43 to 3.71) for those 65 to 74 years and >/=75 years, respectively (both p < 0.001), but gender was not a predictor of death. Common noncardiac conditions associated with death included peripheral vascular disease (adjusted HR 1.50, 95% CI 1.18 to 1.91), pulmonary disease (adjusted HR 1.35, 95% CI 1.10 to 1.66), and renal disease (adjusted HR 1.57, 95% CI 1.25 to 1.99). Many ICD recipients had prior heart failure (46.2%) with an increased HR of 2.33 for death (95% CI 1.96 to 2.76; p < 0.001). Greater comorbidity burden conferred increased risk, with HRs adjusted for age, gender, and heart failure of 1.72 (95% CI 1.44 to 2.05), 2.79 (95% CI 2.15 to 3.62), and 2.98 (95% CI 1.74 to 5.10) for those with 1, 2, and 3 or more noncardiac comorbidities, respectively (all p < 0.001).


CONCLUSIONS
Age, noncardiac comorbidities, and prior heart failure influence survival outcomes in ICD recipients. These factors should be considered in the care of ICD recipients.
Lee
Douglas S
DS
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada. dlee@ices.on.ca
Tu
Jack V
JV
Austin
Peter C
PC
Dorian
Paul
P
Yee
Raymond
R
Chong
Alice
A
Alter
David A
DA
Laupacis
Andreas
A
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D002423:Cause of Death; D015331:Cohort Studies; D015897:Comorbidity; D017147:Defibrillators, Implantable; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors