WOMEN ARE STILL UNDERREPRESENTED IN CORONARY HEART DISEASE RESEARCH: PERSPECTIVES FROM A SYSTEMATIC REVIEW

For decades, women have been neglected in cardiovascular research. With growing evidence to support a connection between the heart and the brain, we systematically reviewed the status of women included in experimental research assessing the impact of coronary heart disease (CHD) on neuropsychological functions.

We conducted a systematic review and used the PRISMA guidelines to report our findings. We screened a total of 26,843 references, of which 418 remained for full-text screening and only 13 were included in the final analysis. Throughout the screening process, we excluded studies which did not include women or participants with CHD or its subtypes (e.g., myocardial infarction, angina pectoris), or did not perform a neuropsychological – or variant - assessment. During the full-text screening, we excluded studies that did not perform separate statistical analyses for sexes or for conditions (e.g., combining CHD and heart failure participants). Close to half of the studies (161 studies; 46.60%) were excluded during the full-text screening phase because there was no separate analysis for women, exhibiting the underwhelming attention given to sex differences in CHD research. Of the 13 studies kept, 11 had samples composed of 36% or fewer women, and all studies, except one, failed to report the power and effect size of their sample. Furthermore, only one study considered menstrual cycle/menopause status, although it is known to influence performance on cognitive testing and CHD progression. Demographic variables that are commonly acknowledged to be cardiovascular risk factors (e.g. cholesterol, hypertension, smoking, etc.) were often measured but rarely compared between sexes, providing an incomplete picture of the underlying factors which affect the women included in these studies.

Our systematic review shows that women are still strikingly underrepresented in CHD research. Based on our findings, we propose the following guidelines: 1) the number of women included in CHD research should be similar to the CHD prevalence in the general population; 2) researchers should calculate the power and effect size of their samples; 3) menstrual cycle or menopausal status should be taken into account; and 4) all demographic variables should be reported separately for men and women. These guidelines aim to improve cardiovascular research in women, so that future research trials can better represent them.