Women subjects in NIH-funded clinical research literature: Lack of progress in both representation and analysis by sex

The National Institutes of Health (NIH) issued guidelines in 1990 requiring the inclusion of women and minorities in all NIH-sponsored clinical resear ch and revised these guidelines in 1994 to require analysis of clinical tri al outcomes by sex of the subjects. To ascertain whether these guidelines a re yet reflected in the scientific literature, we performed a survey of res earch articles published in major medical journals. All original research a rticles in the New England Journal of Medicine, the Journal of the American Medical Association, the Journal of the National Cancer Institute, and Cir culation from the years 1993, 1995, 1997, and 1998 were examined. Articles were assessed for use of human subjects, source of funding, type of study ( clinical trial or not), sex-relatedness of the disease or condition, inclus ion of women as study subjects, and analysis of outcomes by sex of the subj ects. Among NIH-funded, non-sex-specific studies, approximately one fifth o f the studies published each year failed to include women as research subje cts. This number did not improve significantly over the 5-year period analy zed. Only one quarter to one third of the studies that included women analy zed data by sex of the subjects, with no significant change over the time p eriod studied. Although most clinical trials included women as study subjec ts, in only a small percentage of the trials were results analyzed by sex o f the subjects, with no significant improvement over time. These data clear ly show the need for increased awareness and monitoring of recruitment and retention of women in clinical research and for analysis of data by sex of the subjects to be carried out consistently.