Doctors lack female participants in clinical trials

By Terri Coles

TORONTO (Reuters) - Fifteen years after rules limiting female participation in clinical trials were changed, women are still under-represented in research despite evidence that many conditions such as lung cancer and depression have gender-based differences.

Only 9 percent of the female respondents in a survey of 2,000 American adults released this week for Sex Differences in Health Awareness Day had ever participated in medical research, and 93 percent said their doctor had never mentioned the opportunity to them. One quarter was unaware that healthy individuals could participate in medical research.

The situation has left doctors with a lack of study participants and may be leaving women with the short end of the stick when it comes to developing gender-based treatments, like one for lung cancer that is targeted to women because it interacts with estrogen in the tumor.

"As research advanced, we started to recognize more and more that women were not just small men with different plumbing and a hormone problem, that there were real biological differences between men and women that had an impact on whether or not a drug was going to work well or cause side effects," said Sherry Marts, vice-president of scientific affairs at the Society for Women's Health Research, which works to increase awareness of the need for women to be properly represented in medical research.

Before 1993, women couldn't participate in most major medical studies unless they were post-menopausal or had had a hysterectomy, due to fears about the effects of experimental drugs on their offspring. "Here these companies were putting these drugs on the market, and they had never been tested in women but they were being prescribed to women," Marts said.

The Society for Women's Health Research, which commissioned the telephone survey, worked to change that rule and open clinical trials to female participants; the change that year also forced the inclusion of more minorities in trials.

Today, researchers say it's still hard to recruit women for their trials, but Marts said the issue is less a lack of interest and more an unawareness that they're needed. It's hard for women to feel like their participation is valued if every study they're aware of included only men, she said. "One of the truisms around volunteering is that people don't volunteer for things if they don't feel asked."

The survey revealed three main reasons for the hesitation: a lack of time, a lack of interest, and fear about the risks. Study designers work to reduce what they call "hassle factors," Marts said -- the factors that may reduce a person's interest in participating in a study, like the number of clinic visits required or the amount of time needed. For example, she said, many researchers provide on-site child care, and some will even come to a subject's home to ensure their continued participation.

Some of the safety concerns likely have to do with the fact that people often hear about a research study because something bad has happened, Marts said, which may give the public the impression that these studies generally carry a high level of risk.

The Society for Women's Health Research's Some Things Only A Woman Can Do campaign works to let people know that all of the risks any particular study may carry must be fully explained to its participants, who can choose to leave the trial at any point, Marts said. As well, the research protocol itself goes through an intensive review by an ethics board that includes non-scientists as well as scientists; the board must be satisfied that the researchers are doing everything they can to reduce risk to participants before the study will be approved, she said. The United States even has a federal office specifically for the protection of research subjects.

"I think the fear is probably grounded in what they've heard about research," Marts said, "and the reassurance is in what they haven't heard yet."

It's important that trials not only include more female participants, but also do more sex-based analysis of the results, Marts said. When there are women included in the study, it's important to break the data out by gender in order to get the whole picture of how men and women may be affected differently, she said.

It also can be difficult to find participants for studies looking at female-specific health problems. The research team at the National Institute of Mental Health (NIMH) is seeing a decline in the number of women volunteering for their studies, especially those looking at postpartum depression and midlife perimenopausal depression. The stigma associated with these conditions is part of the difficulty in recruiting participants, NIMH investigator Dr. Peter Schmidt said in a statement.

And minority women are a "twofer" who illustrate that there is more than one variable to consider in research, Marts said. It's hard to create a trial with enough participants to do large-scale analysis of multiple variables, she said, so researchers need to figure out which variables are the most relevant and how to design studies that examine those well.

"You start to hit a point where the number of people you'd have to put in a study becomes prohibitive," she said. "Coming up with more creative ways of looking at the data is going to absolutely be critical."

There is good news, however.

More than 70 percent of the survey respondents who had participated in medical research said they would definitely or probably do it again. Those who had chosen to be involved in a study were motivated by a desire to contribute to scientific advancement, a contribution Marts described as substantial.

"For us, what's important is the need to continue to educate people, especially women, about the importance of participation in medical research," Marts said. A woman doesn't have to be ill to participate in a trial, and there are research opportunities that don't involve testing experimental drugs, she said. Healthy volunteers are sometimes needed to test interventions, and observational studies simply track a participant's history or habits instead of introducing treatments or medications.

Clinicaltrials.gov is one resource for people who are interested in participating in medical research. The government-run site lists studies funded by the National Institutes of Health along with research at schools and private institutions. EmergingMed, a for-profit operation, allows patients to register and contacts them for suitable trials. The Center for Information and Study on Clinical Research Participation is a non-profit organization that also runs a clinical trial search.

Have you ever participated in a research study? Would you? Send us your comments: HealthMatters@reuters.com