The study, which will appear in the Feb. 12 issue of the Journal of the American Medical Association, found that people who took carvedilol, a beta-blocker, had a 35 percent decrease in their risk of death compared to those taking a placebo. And the medication didn't increase the risk of side effects such as fluid retention and worsening heart failure.
"This study has good implications for practice," says the author of an accompanying editorial, Dr. Sergio Pinski, section head of cardiac pacing and electrophysiology at the Cleveland Clinic Florida in Weston. "If the medicine is started with careful titration [slowly tweaking the dose of a drug to its most useful level] and follow-up, it can be used safely in even very sick patients. It won't make patients worse, and I think you can start seeing benefits early on."
Many drugs, including carvedilol, must be carefully titrated so that doctors can measure the effects of the drug before increasing the dose. If you start with too high a dose, the risk of side effects is greater.
More than 5 million Americans have been diagnosed with congestive heart failure and more than 550,000 are newly diagnosed each year, according to the American Heart Association. In his editorial, Pinski writes that your lifetime risk of developing heart failure is probably about one in five.
For this study, researchers from Australia, Canada, Switzerland, Poland, England, Germany and the United States, conducted a randomized, double-blind, placebo-controlled study at 334 hospitals in 21 countries. The study included 2,289 volunteers who had symptoms of heart failure, but who were not retaining excessive fluid. To be included in the study, the participants' hearts had to be pumping at less than 25 percent of what is considered normal.
Study participants either received a titrated dose of carvedilol or a placebo. More than 1,100 volunteers started on 3.125 milligrams of carvedilol twice a day and were titrated up to as much as 25 mg two times daily. The study volunteers were followed for the first eight weeks of treatment.
The researchers found that fewer people on carvedilol died or were hospitalized than in the placebo group, and there was no statistically significant increase in serious side effects. The benefits of carvedilol treatment started to become apparent as early as two to three weeks after the start of treatment.
Worsening heart failure was the only problem that occurred in more than 2 percent of the participants, and it occurred with similar frequency in the carvedilol patients (5.1 percent) and the placebo group (6.4 percent).
Pinksi says it's unclear whether these results would be similar for other beta-blockers, but that carvedilol has been used in people with different types of heart failure and has had consistently positive results.
Dr. Dan Fisher, a cardiologist at New York University Medical Center, says this study provides reassurance to doctors who might be reluctant to prescribe beta-blockers for their heart failure patients.
"Because beta-blockers slow the heart rate and lower blood pressure, it seems counterintuitive that they would work in heart failure patients. But what we're learning is that you can give beta-blockers and these patients benefit," says Fisher.
Pinski echoes that sentiment, saying that many doctors who went to medical school 20 or 30 years ago were taught not to prescribe beta-blockers for heart failure.