Are Women With Heart Disease Overlooked and Under Treated?

When it comes to matters of the heart, two new studies prove that men and women are literally very different.

Heart attacks affect about 735,000 Americans every year. While more than half occur in men, more women die from heart disease. In fact, it's their No. 1 killer.

Despite this, women comprise only 24 percent of participants in heart-related studies. Thatís why these two heart studies are so important.

Study 1: How Hearts Change Over Time

Did you know that your heart changes physically as you age? Moreover, men's and women's hearts change differently, according to a new study that examined images of the hearts of nearly 3,000 adults taken ten years apart.

In men, the heart muscle around the left ventricle (one of the lower chambers of the heart) grows and thickens with age, according to investigators led by Johns Hopkins University in Baltimore. Meanwhile, in women, the heart muscle stays the same, or even shrinks slightly. The study, published in Radiology, also found that over time, the heart's filling capacity (the amount of blood the left ventricle can hold between heart beats) reduced in both men and womenóbut more in women. That means women push less blood out to their vital organs with each beat.

Why do these differences matter? "Thereís not enough information in this study to make a huge impact by itself, but it might generate hypotheses [theories] on how to manage womenís heart disease more effectively," says Gregory Thomas, MD, medical director for the MemorialCare Heart & Vascular Institute at Long Beach Memorial Medical Center in California.

"One of the most interesting things it says is that women have smaller organs than men overall, and [that] heart mass tended to stay the same, whereas menís heart mass increased over time," Thomas continues. "We donít know if thatís bad or good, but considering that most heart studies focus on men, itís clear we need to enroll as many women as men in future studies and subdivide the results."

Study 2: Treatment Differences After Heart Attacks

After a heart attack, patients are supposed to be advised to make specific lifestyle changes and take medications to reduce their chances of another one. But many patients arenít prescribed medications or donít take them, according to a study in the journal Circulation: Cardiovascular Quality and Outcomes. And women are more affected than men: Just 65% of women under age 55 started taking appropriate medication after a heart attack, compared to 75% of men the same age.

"In this study, itís striking that women are prescribed guideline-based medications less often than men," Thomas points out. "One reason for this may be that some physicians and patients think the risk for women to have a recurrent MI [myocardial infarction, AKA heart attack] is lower than for men. But thatís not at all true," he says.

"The reality is, women who have one heart attack are at higher risk than men to have another one. That could be because women more often have MIís due to disease of the small vasculature [blood vessels], rather than the large arteries on the top of the heart," Thomas explains. "Because of this physicians, may not perceive the threat of a recurrent MI or cardiac death as being high as it is."

The Other Problem: A Lack of Heart Data on Women

These differences highlight another issue: the lack of data on women from heart studies. As Thomas notes, "About two-thirds of the heart studies done globally primarily evaluate men, so we tend to develop treatments designed for men and wedge women into those same therapies."

Why are so many heart studies done predominantly on men? "Two big reasons," according to Thomas. "In treatment studies, we tend to exclude older people because they often have other health events happen to them that can cause death and disability beside the specific cardiac thing weíre studying. Currently, more women die from heart disease than men but they do it at later ages, most likely because of hormonal protection before menopause. Since women tend to get heart disease 10 years later than men, we exclude a lot of women because of that age cut off."

Furthermore, "We also exclude women of childbearing age because of hormonal protections and because medication studies could affect a fetus. So younger women are left out too. Unintentionally, we end up with two-thirds [of participants in these studies being] men."

What these two new studies confirm is that in terms of drug studies and outcomes, men and women are differentóand their treatments should be too. Thomas concludes, "Asking women to take the same dose of a new medication as men is equivalent to asking women to fit into men's shoes. Not infrequently, the shoe doesn't fit."

Gregory Thomas, MD, reviewed this article.

Resources

Gregory Thomas, MD. Medical Director, MemorialCare Heart & Vascular Institute at Long Beach Memorial. Interview November 10, 2015.

John Eng et al. "Adverse Left Ventricular Remodeling and Age Assessed with Cardiac MR Imaging: The Multi-Ethnic Study of Atherosclerosis." Radiology published online 20 October 2015.

Kate Smolina et al. "Sex Disparities in Post-Acute Myocardial Infarction Pharmacologic Treatment Initiation and Adherence Problem for Young Women." Circulation: Cardiovascular Quality and Outcomes doi: 10.1161/CIRCOUTCOMES.115.001987, published online 13 October 2015.

Centers for Disease Control and Prevention. Page last updated August 10, 2015.

Go Red For Women Editors. "Heart Disease Statistics at a Glance." American Heart Association. Page accessed November 10, 2015.