To determine whether trial-eligible patients who
received a primary prevention ICD as documented in a large national
registry have a survival rate that differs from the survival rate of
similar patients who received an ICD in the 2 largest primary prevention
clinical trials, MADIT-II (n = 742) and SCD-HeFT (n = 829).
Design, Setting, and Patients
Retrospective analysis of data for patients enrolled
in the National Cardiovascular Data Registry ICD Registry between
January 1, 2006, and December 31, 2007, meeting the MADIT-II criteria
(2464 propensity scorematched patients) or the SCD-HeFT criteria (3352
propensity scorematched patients). Mortality data for the registry
patients were collected through December 31, 2009.
Main Outcome Measures
Cox proportional hazards models were used to compare mortality from any cause.
The median follow-up time in MADIT-II, SCD-HeFT, and
the ICD Registry was 19.5, 46.1, and 35.2 months, respectively. Compared
with patients enrolled in the clinical trials, patients in the ICD
Registry were significantly older and had a higher burden of
comorbidities. In the matched cohorts, there was no significant
difference in survival between MADIT-IIlike patients in the registry
and MADIT-II patients randomized to receive an ICD (2-year mortality
rates: 13.9% and 15.6%, respectively; adjusted ICD Registry vs trial
hazard ratio, 1.06; 95% CI, 0.85-1.31; P = .62). Likewise, the
survival among SCD-HeFTlike patients in the registry was not
significantly different from survival among patients randomized to
receive ICD therapy in SCD-HeFT (3-year mortality rates: 17.3% and
17.4%, respectively; adjusted registry vs trial hazard ratio, 1.16; 95%
CI, 0.97-1.38; P = .11).
Conclusions and Relevance
There was no significant difference in survival
between clinical trial patients randomized to receive an ICD and a
similar group of clinical registry patients who received a primary
prevention ICD. Our findings support the continued use of primary
prevention ICDs in similar patients seen in clinical practice.
clinicaltrials.gov Identifier: NCT00000609