Gender differences in heart failure

Women tend to live longer with heart failure than do men, and they also tend to have a less severe form of the disease, which is characterized by reduced performance of the heart muscle, according to a study by Duke University Medical Center cardiologists.

Having a better understanding of gender differences in heart failure may help physicians to more effectively tailor prevention or treatment strategies to specific patients, the researchers said, adding that studies to date have provided relatively little insight into such differences.

"There is limited data available to help us understand the differences between the genders when it comes to the causes of heart failure and how patients fare with the disease," said cardiology fellow Camille Frazier, M.D., who presented the results of the study on Tuesday, Nov. 14, at the annual scientific sessions of the American Heart Association, in Chicago.

"As we uncovered in our analysis, there are important differences between men and women who have heart failure," Frazier added. "These differences not only point to fertile areas for future research, but can help us to deliver better quality care to our patients."

The study was supported by Duke's Division of Cardiology.

Heart failure is a condition marked by the inability of the heart muscle to pump enough blood to the body's tissues. Despite its name, not everyone with the disease dies immediately, and many people live for years. It is estimated that 50 percent of heart failure patients die within five years of initial diagnosis.

In their analysis, Frazier and colleagues studied the two most common forms of heart failure: ischemic and nonischemic. In the ischemic form, an individual's heart muscle is either damaged or killed over time as blood flow to the heart is reduced, usually by a blockage in the coronary arteries, and the heart is deprived of its needed supply of oxygen. This condition frequently leads to a heart attack. In the nonischemic form, the individual has had no prior history of severe coronary artery disease and has not experienced a heart attack.

The team pooled the data from five clinical trials in which participants received drugs to treat heart failure. In total, the trials included 11,642 patients, approximately 24 percent of whom were women.

The women tended to be older and more ethnically diverse than the men, and they had greater incidences of diabetes and high blood pressure, the researchers said. The women also tended to report more symptoms and to be hospitalized more often than men.

"In general, women and heart disease has not been well studied, and heart failure has been even more poorly studied," said Pam Douglas, chief of cardiovascular medicine at Duke, past president of the American College of Cardiology and senior member of the study team. "We didn't have good evidence for what the gender differences might be, because the numbers of women involved in trials have been so small.

"In our current study, we were able to obtain larger numbers by combining data from the five different trials," Douglas added. "Knowing more about the gender differences will help us make decisions about treatment, such as how aggressively to follow patients or which medication would be the most effective."

Among all of the patients in the combined study pool, 2,400 of them died, Frazier said. Of the patients with ischemic heart failure who died, 18.6 percent were women and 20.9 percent were men. Among patients with nonischemic heart failure who died, 18.2 percent were women and 21.9 percent were men.

"Our data demonstrated that women had better survival rates than men, and patients with nonischemic heart failure fared better than patients with ischemic heart failure," Frazier said.