Women Still Underrepresented in Clinical Study Patient Groups

How Can We Fix That?

Almost 30 years after the US FDA rescinded a ban on women of “childbearing potential” from participating in clinical studies, women remain underrepresented in many key areas for medical trials—including cardiovascular medicine. This is despite guidance that the sexes may respond differently to certain treatments, due to the biological differences between them. One recent study published in Circulation found women accounted for around 38 percent of patients in cardiovascular clinical trials conducted between 2010 and 2017. The numbers for certain trials however—most notably heart failure trials—are considerably lower.


Dr. Valentina Kutyifa, University of Rochester Medical Center
With the underrepresentation of women in these studies we just simply don't have good enough data.
Dr. Valentina Kutyifa, University of Rochester Medical Center

The underrepresentation motivated Dr. Valentina Kutyifa of the University of Rochester Medical Center and Dr. Jeanne Poole of the University of Washington Medical Center to undertake the BIO-LIBRA study. BIO-LIBRA aims for at least 40% female enrollment out of 1,000 patients from 50 centers in the United States. The BIOTRONIK-sponsored trial will investigate whether there is any difference between the sexes in the outcomes of patients with non-ischemic cardiomyopathy, who have been implanted with a defibrillator or are receiving cardiac resynchronization therapy. Because women are often underrepresented in heart failure trials, there is still not enough data to determine whether or not there are differences in outcomes by sex.

Dr. Jeanne Poole, University of Washington
We’ll be able to better identify patients at greatest risk for needing a defibrillator because this is a big need.
Dr. Jeanne Poole, University of Washington

Despite the challenges of the current pandemic, study investigators have been able to enroll about 500 patients in the BIO-LIBRA study so far—46 percent of them women—in a field where only 20-30 percent of women were enrolled in prior studies. Dr. Kutyifa says one of the most important measures they took involved creating enrollment materials that were specifically targeted to women—rather than to an assumed general audience. “We know from previous studies and surveys that women tend to take decisions about enrolling in clinical studies over a longer period of time,” says Dr. Kutyifa. “That’s likely because they often take time to consult with their families and friends before providing informed consent for a clinical study.” Bearing this in mind, study investigators are briefed to expect that women may need a bit more time, as well as information brochures specifically tailored to them. However, this doesn’t mean they are any less interested in participating than men might be.

Dr. Kutyifa points out other factors that may contribute to the underrepresentation of women in heart failure trials specifically—such as the fact that women often develop heart failure later in life than men do, but that specific education and enrollment materials, for both patients and physicians, can help boost participation to a level that adequately represents such a large patient group. In addition to containing information specifically for women, BIO-LIBRA’s patient material also uses images that reflect the lives of the patients it seeks to enroll. As investigators mark the halfway point to the 1,000 patient goal, Dr. Kutyifa says she’s confident that the nearly even patient composition will make BIO-LIBRA the first properly powered study evaluating outcomes in women vs. men receiving implantable defibrillators to treat non-ischemic cardiomyopathy.