Objectives: We compared characteristics and mortality of patients from a community population meeting enrollment criteria of the second Multicenter Automatic Defibrillator Implantation Trial (MADIT II) to those of the MADIT II subjects.
Background: MADIT II showed that implantable cardioverter-defibrillators (ICDs) reduce mortality in patients with myocardial infarction (MI) and low left ventricular ejection fraction (LVEF) <or=30%.
Methods: We used the resources of the Marshfield Epidemiologic Study Area (MESA), a well defined geographic region to identify MADIT II-type patients and determined outcomes during a 2-year follow-up period.
Results: Of 1,126 patients who survived an MI, 114 (10.1%) had an LVEF <or=30%, 30 had exclusions leaving 84 patients meeting MADIT II-eligibility with a prevalence of 1.95/1,000. Applied to the US population, there would be about 360,000 MADIT II eligible individuals. MESA patients were older and more likely to be women than their MADIT II counterparts. The cumulative probability of death at 2 years in MESA patients (22.7%) was similar to the MADIT II control group (22%), whereas the sudden cardiac death (SCD) rate was lower in MESA (2.6%) than in MADIT II control patients (12%).
Conclusions: Differences in demographics, clinical characteristics and risk of SCD in community patients could alter the effectiveness and cost-effectiveness of ICD therapy from results reported in clinical trials. Further research is urgently needed to determine if the evidence-base used to formulate practice guidelines should be generalized to all individuals who meet eligibility criteria for ICD therapy.