Hundreds of thousands of women at risk for irregular heart rhythms have a small, battery-powered gadget embedded in their chests. The implantable cardioverter defibrillator (ICD) can be a lifesaver, shocking a dangerously fast heartbeat back to normal. Yet the actual benefit to women is uncertain, because ICDs were approved by the Food and Drug Administration (FDA) based on clinical trials made up mostly of men. That's typical of testing of many high-risk devices, according to medical reports. And even in the clinical device trials that do include women, generally the outcomes aren't reported by sex.
The result is a critical gap in the data doctors rely on when making decisions about a treatment's benefits and risks for women. It can also pose troubling dilemmas later on, said cardiologist Rita F. Redberg, a professor of medicine at the University of California, San Francisco. That was the case in 2009, when data pooled from clinical trials showed that ICDs were no better than drugs at reducing a woman's risk of death.
"The time to collect data in both sexes is before FDA approval," said Redberg. "Especially with implanted devices, where there's no going back."
Only recently has the FDA proposed guidelines to improve the representation of women in clinical device trials. Intended for the medical device industry, which sponsors most of the research submitted for review, the guidelines are expected to become final by year's end. Similar standards for drug testing were put in place some 20 years ago, following a long period during which women of childbearing age were explicitly excluded from most studies.
In practice, the vast majority of medical devices reviewed by the FDA are cleared for use without human testing if they are deemed "substantially equivalent" to devices already on the market. Only 1 percent of devices undergo rigorous review and clinical trials before they can be marketed.
Even so, the new guidelines for device trials are an important advance, experts say. The proposed FDA guidelines are nonbinding, however, and some experts who favor the new recommendations are skeptical that the medical device industry will comply.
"Industry is always most attentive to the bottom line," said Christine Carter, vice president for scientific affairs at the Society for Women's Health Research (SWHR) in Washington. "So companies will continue to lament that trials are expensive and that recruiting more women is a problem." Device makers will change their study protocols just enough to meet FDA requirements, Carter predicted, but protocols will be "less than ideal for those of us concerned with sex differences and women's health."