An international study of almost 4,000 people with heart failure finds that adding the beta-blocker metoprolol to standard treatment increases survival by about 35 percent. The results are so positive that the study was stopped three years earlier than planned so that all participants could be offered the beta-blocker drug. Results of the study will be presented at the 71st Annual Scientific Sessions of the American Heart Association in Dallas on November 10.
"With this large study, we now know that by adding beta-blocker therapy to our standard treatments for heart failure, we can save many more lives," says Stephen Gottlieb, M.D., a cardiologist who directs the heart failure service at the University of Maryland Medical Center in Baltimore. Dr. Gottlieb, who also is an associate professor of medicine at the University of Maryland School of Medicine, was the U.S. National Co-Director of the study.
Doctors have been reluctant to give beta blockers to people with congestive heart failure, because they initially reduce the heart's pumping ability, according to Dr. Gottlieb. "However, when given carefully, starting with a very low dose and gradually increasing the dose, the long term effect is to increase cardiac function and improve survival," he adds.
Beta-blockers are routinely prescribed for several medical conditions, including hypertension. They also are recommended for patients following a heart attack.
The study, called Metoprolol CR/XL Randomized Intervention Trial in Heart Failure (Merit-HF), was conducted in the United States and 13 other countries. It was sponsored by Astra AB of Sweden, the company that manufactures metoprolol. Of the 3,991 heart failure patients in the study, 1,071 were from the United States.
The study began in February 1997 when participants were randomly assigned to receive either the beta-blocker or a placebo. The study was stopped on October 31, 1998, when the study's Independent Safety Committee observed the significant results.
Heart failure, in which the heart does not pump enough blood to meet the body's demands, is an increasing problem both in the United States and in Europe. It affects at least four million people in the United States, with about 400,000 new cases diagnosed each year. It results in almost one million hospitalizations each year and is the most common discharge diagnosis in patients over age 65.