CHICAGO — Atenolol may be as effective as carvedilol for improving survival and reducing hospitalizations in patients with systolic heart failure, based on a retrospective review of more than 1,000 unrandomized patients.
The finding suggests that atenolol should be tested in a prospective, randomized study to definitively test whether it works as well as carvedilol in patients with heart failure, Dr. John R. Kapoor and his associate said in a poster presented at the annual meeting of the American College of Cardiology.
Currently, the only β-blockers approved by the Food and Drug Administration for use in patients with heart failure are carvedilol and metoprolol succinate, an extended-release formulation of metoprolol, said Dr. Kapoor, a cardiologist at Stanford (Calif.) University. Another β-blocker, bisoprolol, has also proved to help patients with heart failure, but in the United States bisoprolol is approved only to treat hypertension. Atenolol, another β-blocker, is not approved by the FDA for treating heart failure but is often prescribed for that purpose, Dr. Kapoor noted.
To estimate atenolol's efficacy in heart failure patients, the Stanford researchers reviewed 1,385 consecutive patients who had their left ventricular ejection fraction measured by echocardiography at the VA Palo Alto Health Care System during 1998 and 2004 and were found to have an ejection fraction of 40% or less. The study then focused on the 1,162 patients from this group who were treated with either carvedilol, atenolol, or metoprolol tartrate (an immediate-release formulation of metoprolol). The primary outcome of the analysis was death within the following 6 months; secondary end points were heart failure hospitalization, and death plus hospitalization during 6 months of follow-up. The average age of the patients was 68, and virtually all of the patients were men.
The mortality rate was lowest, 1.3%, among the 251 patients (22%) treated with atenolol. Among the 611 patients (53%) treated with carvedilol, 2.5% died; and among the 300 (26%) treated with metoprolol, 6% died.
After adjustment by a propensity score analysis, patients treated with atenolol had a slightly reduced risk of death, compared with patients treated with carvedilol, but the difference between the two drugs was not statistically significant. After propensity score adjustment, patients treated with metoprolol tartrate were about twice as likely to die as were patients treated with atenolol, a difference that just reached statistical significance.
Adjusted analyses were not reported for the secondary end points. Unadjusted findings showed that the patients treated with atenolol consistently fared better than did those treated with either carvedilol or metoprolol tartrate for both heart failure hospitalizations and for hospitalizations plus deaths. Atenolol treatment was linked with superior outcomes at 90 days, 1 year, and 2 years after the start of treatment.