Gender representation in trials.

The perception is that women have been understudied relative to men. It has been sufficient to cause Congress to enact legislation to require that a clinical trial must be "designed and carried out in a manner sufficient to provide for a valid analysis of whether the variables being studied in the trial affect women ellipsis differently than other subjects in the trial." We looked for evidence as to whether the perception has a basis in fact by looking at measures of gender-based research effort. Clinical trials, published between 1966 and 1998 in U.S. journals and indexed in MEDLINE, were classified by gender. Reports of trials appearing in five widely circulated medical journals (Annals of Internal Medicine, British Medical Journal, Journal of the American Medical Association, Lancet, and New England Journal of Medicine) in 1985, 1990, and 1995 were retrieved and read to obtain counts of the numbers of males and females represented in trials published in those journals. For reports of trials published in U.S. journals, the percent involving males and females, males only, females only, and those where gender was not specified were 55.2%, 12.2%, 11.2%, and 21.4%, respectively. Counts of males and females represented in the reports of trials appearing in the five aforementioned journals were 355,624 and 550,743, respectively. We did not find evidence of systematic effort bias against females.