Men and women may also respond differently to treatment, raising concerns about whether current practices provide the best care and reinforcing the urgency for sex-specific clinical trials for heart failure.
The data show that HF, a life-threatening condition in which the heart cannot pump enough blood throughout the body, affects women at an older age and often with a stronger heart compared to men. Hypertension and valvular disease are more likely the culprits for HF in women, whereas men are more likely to have coronary artery disease (CAD) as the underlying cause. And while women live longer with the disease, they also tend to have lower quality of life than men due to greater physical limitations with exercise, more HF-related hospital stays and depression.
"Current practice is to treat heart failure similarly in men and women," said Eileen Hsich, M.D., director of the Women's Heart Failure Clinic at the Cleveland Clinic in Ohio. "Yet, our review of published reports suggests compelling sex differences, not only in terms of how and when heart failure develops, but also possible responses to treatments and how the disease impacts quality of life."
For example, "normal" values for brain natriuretic peptide—a biomarker that is being used more frequently to identify patients with symptoms of HF and stratify patients by risk—are higher for women versus men and abnormal values with a BNP > 500 pg/ml may be a stronger predictor of death in women with HF than in men. There is also evidence that sex-specific differences may result when performing a cardiopulmonary stress test, which is often used to evaluate patients for heart transplantation. Women with HF tend to have a better prognosis for any given peak oxygen consumption value when compared to men, yet the cut-off values to determine need for heart transplantation are the same for both sexes. The potential benefits of certain HF therapies both in terms of reducing morbidity and mortality appear to be different among women.
"We found that some of the available medications may not be as effective in women, while other therapies, for example, beta blockers, aldosterone antagonists and pacemakers, may be very beneficial," said Dr. Hsich, although she cautions that these finding should in no way prompt women to deviate from what their doctor recommends.
"We need to remember that the therapy women are receiving must be working because they are living longer," she added. "Still, we need to gain a better understanding of HF in women so that we know whether we are providing the best possible care."
A critical challenge remains enrolling women in clinical trials and inspiring researchers to conduct sex-specific studies.
"This is a disease that affects women just as much as men, yet it remains poorly understood and women are still underrepresented in studies," said Dr. Hsich, adding that major multicenter HF trials in the last decade on average only included 28 percent women. "It is really important for women to speak up and not wait for their doctor to approach them about participating in a clinical trial. In doing so, we can help ensure that future advances in HF treatments are applicable to women and supported by sound research."