Representation of women in randomized clinical trials of cardiovascular disease prevention.
BACKGROUND
The 2007 American Heart Association guidelines for cardiovascular disease prevention in women drew heavily on results from randomized clinical trials; however, representation of women in trials of cardiovascular disease prevention has not been systematically assessed.


RESULTS
We abstracted 156 randomized clinical trials cited by the 2007 women's prevention guidelines to determine female representation over time and by clinical indication, prevention type, location of trial conduct, and funding source. Both women and men were represented in 135 of 156 (86.5%) trials; 20 trials enrolled only men; 1 enrolled only women. Among all trials, the proportion of women increased significantly over time, from 9% in 1970 to 41% in 2006. Considering only trials that enrolled both women and men, female enrollment was 18% in 1970 and increased to 34% in 2006. Female representation was higher in international versus United States-only trials (32.7% versus 26.7%) and primary versus secondary prevention trials (42.6% versus 26.6%). Female enrollment was comparable in government/foundation-funded versus industry-funded trials (31.9% versus 31.5%). Representation of women was highest among trials in hypertension (44%), diabetes (40%), and stroke (38%) and lowest for heart failure (29%), coronary artery disease (25%), and hyperlipidemia (28%). By contrast, women accounted for 53% of all individuals with hypertension, 50% with diabetes, 51% with heart failure, 49% with hyperlipidemia, and 46% with coronary artery disease. Sex-specific results were discussed in only 31% of primary trial publications.


CONCLUSIONS
Enrollment of women in randomized clinical trials has increased over time but remains low relative to their overall representation in disease populations. Efforts are needed to reach a level of representation that is adequate to ensure evidence-based sex-specific recommendations.
Melloni
Chiara
C
Duke Clinical Research Institute, Duke University Medical Center, Durham, NC 27705, USA. mello004@mc.duke.edu
Berger
Jeffrey S
JS
Wang
Tracy Y
TY
Gunes
Funda
F
Stebbins
Amanda
A
Pieper
Karen S
KS
Dolor
Rowena J
RJ
Douglas
Pamela S
PS
Mark
Daniel B
DB
Newby
L Kristin
LK
D000367:Age Factors; D000572:American Heart Association; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control*; D004345:Drug Industry / Q000191:economics; D019317:Evidence-Based Medicine; D005260:Female; D005380:Financing, Government; D054624:Health Status Disparities; D006801:Humans; D008297:Male; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D011322:Primary Prevention; D016032:Randomized Controlled Trials as Topic / Q000191:economics / Q000379:methods*; D035842:Research Subjects; D012109:Research Support as Topic; D055502:Secondary Prevention; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D016387:Women's Health; D014932:Women's Health Services