The study's main endpoints were time to death from any cause, and time to either death or hospitalization for cardiovascular causes. Patients were followed for a mean of 16 months, starting during the hospitalization for their initial heart attack. They were monitored regularly.
To qualify for EPHESUS, patients had to have had a heart attack within 3 to 14 days before enrolling in the study, and had to have a left-ventricle ejection fraction (pumping ability) of less than 40 percent of normal. Those who did not have diabetes had to have signs of heart failure such as abnormal heart and lung sounds.
Patients in the study received optimum therapy, which could have included ACE inhibitors, aspirin, angiotensin-receptor blockers, diuretics, beta-blockers and coronary reperfusion. Patients in the treatment arm were started on 25 milligrams of eplerenone, and after one month the doses were increased to a maximum of 50 mg; the mean dose was 43 mg.
The mean age of patients at baseline was 64 years, and they were on average randomized to treatment or placebo 7.3 days after their heart attack. About a third had diabetes, 60 percent had hypertension, and only 14 percent had a prior diagnosis of heart failure.
The results show that the number of treated patients needed to save one life in a year is 50, and the number needed to prevent a cardiovascular-related death or hospitalization in a year is 33.
Patients who had the worst ejection fractions, less than 30 percent, had the largest reduction in sudden cardiac death -- 37 percent. These same patients are considered by some to be prime candidates for implanted defibrillators because of their extremely high risk for instantly lethal events known collectively as sudden cardiac death. But eplerenone greatly reduced this risk.