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Varosy PD (SFVAMC/UCSF), Pellegrini CN
(SFVAMC/UCSF), Yang YY
(SFVAMC/UCSF), Wang N
(SFVAMC), Singh R
(SFVAMC), Slomiak S
(SFVAMC), Keung EC
(SFVAMC/UCSF), Massie BM
(SFVAMC/UCSF)
Objectives:
Randomized trials have demonstrated that implantable cardioverter-defibrillators (ICDs) reduce mortality by 23-54% among patients at risk for sudden cardiac death, but even with an ICD in place for the primary prevention of sudden cardiac death, two-year mortality in these trials ranged from 11-16%. Outcomes among real-world populations outside trials are less clearly established. We sought to determine the burden of comorbidities and mortality among veterans with ICDs.
Methods:
Among veterans who received a first ICD within the VA and enrolled in the VA National ICD Surveillance Center within three months of implantation between January, 2003 and December, 2006, we ascertained baseline characteristics and mortality by formal abstraction from the electronic medical record and query of the social security death index. Mortality was estimated by the method of Kaplan and Meier.
Results:
After excluding patients implanted with cardiac resynchronization devices, a total of 1765 subjects met our study criteria; most (85%) were implanted for the primary prevention of sudden cardiac death. Veterans with ICDs were overwhelmingly male (99%), and most had coronary artery disease (87%). The mean age was 66±10 years, and there was a high prevalence of diabetes mellitus (46%), chronic kidney disease (24%), history of cancer (12%), and peripheral arterial disease (30%). Mortality among veterans with ICDs was 2.9% (95% CI, 2.1—3.8%) at one year, and 10.3% (95% CI, 9.0—11.9%) at two years.
Implications:
Although veterans were older and had greater burden of comorbidity, mortality among veterans after cardioverter-defibrillator implantation was lower than was observed in the device arms of the randomized trials of primary-prevention ICD therapy. Whether this difference is due to improvements in the care of cardiac patients since the trials were published, better selection of candidates for ICD therapy within the VA, or other factors is unclear.
Impacts:
Despite a high burden of comorbidity, mortality among veterans with ICDs is surprisingly low.
