The government has had mixed success in its 15-year push to enroll more women in heart studies, researchers say.
The effort grew out of a recognition that women were underrepresented in studies of new drugs, new procedures and risk factors for heart disease and stroke. Researchers realized that women tend to get sick about 10 years later in life but live longer, so that their lifetime risk of heart disease is about the same as men's.
In a study published in Thursday's New England Journal of Medicine, researchers led by University of Wisconsin-Madison cardiologist Pamela Douglas looked at 121 clinical trials on cardiovascular disease funded between 1965 and 1998 by the National Heart, Lung and Blood Institute.
The three lowest years for female participation were for tests beginning in 1972, 1973 and 1981 - all less than 5 percent. The three highest years - all above 80 percent - were 1991, 1992 and 1996.
During the 33-year period, women accounted for 54 percent of all test subjects, though they represent just 49 percent of heart patients nationwide.
But Douglas was disappointed to find that women were just 38 percent of participants in mixed-sex studies. Also, much of the overall progress stemmed from two women-only studies each with tens of thousands of patients in the early 1990s.
Women represented just 26 percent of participants in the total of six studies of congestive heart failure. Most of the studies focused instead on high blood pressure and coronary artery disease.
About 60 million Americans suffer from some kind of cardiovascular illness, which leads all diseases in killing about 950,000 a year.
Some critics say male scientists have been more interested in treating the health problems of men. Others say that pregnancies and the childbearing potential of women legitimately keep many from participating in studies.
Spokesmen for the heart institute said they want to look at what is behind the relative scarcity of women in heart failure studies. They added that the small number of tests in that area may be misleading.
''When you look overall and at some of the major categories, we're doing very well,'' said Dr. Larry Friedman, a special assistant at the institute.