Beta-blockers, such as metoprolol (Lopressor, Toprol XL) are used to treat high blood pressure and chest pain (angina), and to prevent recurrence of a heart attack in people with heart failure. Several large studies have demonstrated that beta-blockers prevent deaths and future heart failure events in men with chronic heart failure. But the evidence that beta-blockers have the same effect in women has been inconclusive. Now, a study published in Circulation: Journal of the American Heart Association provides new evidence that beta-blockers may in fact work just as well in women as they do in men.

About the study

Researchers affiliated with AstraZeneca Pharmaceuticals, the company that manufactures the beta-blocker metoprolol, conducted this study. AstraZeneca also sponsored the study. The researchers analyzed data from the Metoprolol Controlled-Release Randomized Intervention Trial in Heart Failure (MERIT-HF)—a study of the effects of metoprolol versus placebo in 3991 heart failure patients.

Participants in MERIT-HF were between the ages of 40 and 80, were being treated for chronic heart failure for at least three months, and were taking diuretics and ACE inhibitors (other drugs for heart failure). Participants were randomly selected to receive either metoprolol or a placebo (an inactive pill). The MERIT-HF study was conducted from February 14, 1997 to October 31, 1998, with an average of one year of follow-up per participant.

One part of the study's analysis involved a closer look at the 898 women in the MERIT-HF study. The researchers compared the number of deaths and hospitalizations among women taking metoprolol versus women taking the placebo.

In a separate analysis, they pooled the data on women in the MERIT-HF study with data from two similar studies of other beta-blockers to analyze the effects of beta-blockers in a larger group of women with heart failure.

The findings

Among women taking metoprolol, there was a 21% reduction in deaths and hospitalizations (combined measure) per patient per year than in the placebo group. There was also a 29% reduction in hospitalizations for cardiovascular problems and a 42% reduction in hospitalizations for heart failure.

In comparison to the 21% overall reduction in deaths and hospitalizations among women, metoprolol reduced deaths and hospitalizations among men in the study by 18%.

The pooled data from the three beta-blocker studies showed that beta-blockers increased survival to a similar degree among both women and men.

There are limitations to this study, however. Ninety percent of the women in this study were white, so these results may not apply to women of other racial and ethnic groups. In addition, the researchers reanalyzed data from a previous study that comprised only 25% women and that was not designed to assess the effectiveness of metoprolol specifically in women.

How does this affect you?

Does this mean that female heart failure patients should be given beta-blockers? The findings of this study suggest that beta-blockers are effective in female heart failure patients. If you're a woman being treated for heart failure and your doctor has not prescribed beta-blockers, you may want to ask him or her about considering beta-blockers. Your doctor will assess your individual situation and determine whether beta-blockers are a good option for you.