Exclusion of Women From Clinical Research: Myth or Reality? Wendy A. Rogers; Angela J. Ballantyne; for the Australian Gender Quity In Health Research Group. Mayo Clin Proc. 2008;83(5):536-542.

Dispelling the Myths: Calling for Sex-Specific Reporting of Trial Results. Sharonne N. Hayes; Rita F. Redberg. Mayo Clin Proc. Editorial: 2008;83:523-525.  [ Download PDF ]

Editorial

Extract. Exclusion of women from clinical trials has its origins in the centuries-old concept of protecting women and children from harm. The logical result of this effort was that women of childbearing age were barred from participating in most medical research. Unfortunately, this reasonable, if somewhat paternalistic, effort to avoid harming fetuses by not enrolling pregnant participants in early-phase drug trials was overenthusiastically expanded to a virtual ban on all women in clinical trials. Additional reasons given for excluding women from research studies include the real and perceived challenges of “controlling” for cyclic hormonal effects on outcomes and the widely held assumption that any results derived from male-only research could be applied to women.

Sex-based medicine traditionally has been thought of as the study and treatment of conditions affecting only men or only women, such as reproductive health and sex-specific cancers. Only in the past decade or so have researchers widely recognized the many biological differences between the sexes. Sex-based differences in natural history of disease, epidemiology, pathophysiology, diagnostic accuracy of tests, response to therapy, and outcomes have all been identified in a range of diseases and conditions previously thought to be “gender neutral.” Despite findings in 1985 from the US Public Health Service Task Force on Women’s Health Issues1 that excluding women from clinical studies had led to a lack of knowledge about women’s biology and that this deficiency had compromised the health of women, male domination in clinical trial enrollment continued.

Exclusion of Women From Clinical Research: Myth or Reality? Wendy A. Rogers; Angela J. Ballantyne; for the Australian Gender Quity In Health Research Group. Mayo Clin Proc. 2008;83(5):536-542.

Abstract

Objective. To determine the proportion of male and female research participants and rates of sex-based analysis and sex-specific reporting in published Australian clinical research.

Participants And Methods. We assessed 400 clinical studies involving Australian-only participants, published in journals between January 1, 2003, and May 31, 2006 (100 per year). Numbers of male and female participants in each study and presence or absence of analysis by sex (covariate adjustment, subgroup analysis, or sex-specific reporting) were recorded. Sex-specific studies were evaluated to determine whether the exclusion of one sex was biologically necessary.

Results. The total sample comprised 546,824 participants, of whom 73% were female; 36 studies were male-only, 78 were female-only. Of the participants in 286 studies that were not sex-specific, 56% were female. Of 114 sex-specific studies, the segregation by sex was deemed to be biologically necessary in 62%, ie, the research related directly to male or female biological function. More than one-quarter (28%) of studies with 30 participants or more published covariate adjustment or subgroup analysis by sex; 7% included sex-specific reporting of results.

Conclusion. We found no routine exclusion of women; however, few publications analyzed results by sex. Some studies excluded women or men for apparently arbitrary reasons. Research performed with male-only participants differed in nature and size from that performed with female-only participants. These data indicate the need to track the sex of research participants. In addition, they provide the basis for assessing appropriate inclusion of men and women in research and for comparing any relationship between different international regulatory models and the rates of female participation in research.