Medical Devices and Gender Differences, Studies of Both Sexe

by Food and Drug Administration (FDA)

(Page 3 of 4)

Medical Devices and Gender Differences

Men and women may also respond differently to certain medical devices and the procedures in which they are used. Several FDA studies have focused on identifying some of these differences.

In 2003 and 2004, FDA researchers studied more than 150,000 people with suspected heart disease and found that women had about twice the risk of men for local complications after cardiac catheterization. In the catheterization procedure, a slender tube is inserted into a large artery in the leg (femoral artery) and is threaded up through the body to the heart to diagnose or treat narrowed heart arteries that block blood flow.

"The study was done to look at risks associated with hemostasis devices," says Dale Tavris, M.D., M.P.H., an FDA epidemiologist specializing in preventive medicine. These devices are used after cardiac catheterization to prevent continued bleeding of the femoral artery where the catheter is inserted.

We don't know why complications, such as hemorrhaging, occurred more in women, says Tavris. "There's speculation that it may be due to blood vessel size or hormonal differences. And the risk applies whether or not the hemostasis devices are used." Further information is needed to understand these occurrences, says Tavris, before we can determine whether any changes to the catheterization procedure or to hemostasis devices or their labeling are appropriate.

An FDA-sponsored study at Boston University involves men and women with diabetes who are using blood glucose monitors at home to test their blood several times a day. Researchers are looking for any differences in testing blood drawn from the fingertip or from another part of the body, since newer glucose monitors use blood samples from alternate body areas. "We found that the fingertip can have a different glucose value from an arm or leg, especially when sugar levels are changing rapidly, for example, after a meal or after exercise," says Jean Cooper, D.V.M., director of the Division of Chemistry and Toxicology in the FDA's Center for Devices and Radiological Health. The study is continuing to determine whether gender might be a factor in this difference in glucose values.

The FDA now requires glucose monitors to carry a warning label cautioning against using alternate sites when glucose levels are changing rapidly. If a manufacturer can show in clinical trials that its device doesn't demonstrate this variance, the warning is not required.

Studies of Both Sexes

In 1977, an FDA guidance said that women able to become pregnant should not participate in the early phases of drug studies, with an exception for studies of potentially life-saving drugs. The exclusion reflected the concern that if a woman became pregnant, the baby might have birth defects.

Over more than two decades, the FDA has worked to ensure that both women and men are represented fairly in clinical trials involving drugs, biologics such as vaccines and blood products, and medical devices.

In 1988, the agency issued guidance to drug makers asking that the safety and effectiveness data in drug applications be analyzed according to gender, age, and race. And, in 1993, the agency issued its Guideline for the Study and Evaluation of Gender Differences in the Clinical Evaluation of Drugs, known as the gender guideline.

When the gender guideline was published, the FDA also revoked the 1977 restriction on women of childbearing age in early drug studies and reiterated the need to include patients of both sexes in the development of drugs, biologics, and medical devices. The guideline also recommended that drug companies analyze separately men's and women's responses to drugs.

Attention to potential gender differences became part of a larger agency effort to ensure that the safety and effectiveness of drugs are adequately studied in people who represent the full range of patients who could use the drugs when approved. In a 1998 regulation known as the Demographic Rule, the FDA again addressed the importance of collecting data on clinical trial volunteers by gender, race, and age. The regulation required companies to analyze the data to look for possible differences in effectiveness, safety, and dose-response and to submit this information in applications for new drugs. It also required reporting demographic data in annual reports during a drug's investigation phase.

A regulation in 1999 gave the agency the authority to halt studies of new drugs to treat life-threatening diseases if clinical trials excluded women solely because they could become pregnant.

"The Demographic Rule and gender guideline represent our commitment to looking at possible differences in various subgroups' response to drugs, whether men and women, black and white, old and young," says Robert Temple, M.D., director of the FDA's Office of Medical Policy. "The guidance tells drug sponsors what our expectation is and what we're looking for."

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.