Closing the Gap: Addressing Underrepresentation of Women in Cardiovascular Clinical Trials

CVD affects nearly 60 million women in the United States, of which only about 44% recognize it as a significant health threat.¹ This is largely due to prioritizing male enrollment in cardiovascular clinical trials, subsequently leading to underrepresentation and inadequate treatment options for women with CVD. Despite awareness of treatment and clinical trial inequality amongst men and women, multiple studies published from 2021 to 2024 find ongoing representation challenges in cardiovascular studies, such as coronary revascularization trials. Women’s underrepresentation in cardiovascular trials has significant consequences for health outcomes and knowledge of women’s biology, often limiting access to antiplatelet therapies and other treatments for CVD.

The underrepresentation of women in cardiovascular clinical trials remains a critical issue with far-reaching implications for both treatment outcomes and our understanding of CVD management.

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Antiplatelet therapy is widely accepted as a treatment for individuals with CVD. However, underrepresentation of women in these trials has led to limited understanding of the efficacy, adverse effects (AEs), or outcomes of this therapy. In a study published in JAMA Cardiology, authors found that among all types of cardiovascular clinical trials, only 27% of women were enrolled across 141 coronary artery disease trials and 61 acute coronary syndrome trials from 2010 to 2017.²

Currently, health care professionals have more comprehensive knowledge of men’s responses to CVD therapies over women due to men’s prevalence in clinical trials. Dissimilarities in women’s and men’s hormones, platelet reactivity, P2Y12 inhibitors, and likelihood of developing comorbidities greatly impact responses to treatment.³ Increased likelihood of AEs experienced during CVD therapies in women may be due to absorption, body composition, distribution, metabolism, or hormone changes.⁴ These disparities not only affect treatment outcomes but also hinder physicians' understanding of optimal dosing, effectiveness, and AEs of cardiovascular therapies.

A study published in the Journal of the American Heart Association presented an analysis of the enrollment data from 51 randomized trials and discovered that, out of the total 25,425 patients enrolled, only 5029 patients were women, representing 20.8% of participants (95% CI, 17.6–24.4; range, 0.5%–57.9%).³ Despite evidence of women's increased adverse responses to cardiovascular drugs compared to men, with a risk that is 1.5 to 1.7 times higher, as well as higher rates of hospital admissions related to cardiovascular events, an additional study reports that CVD therapy and drugs often fail to report findings based on sex.⁵

The underrepresentation of women in cardiovascular clinical trials remains a critical issue with far-reaching implications for both treatment outcomes and our understanding of CVD management. Despite strides in awareness, persistent disparities in enrollment rates interrupt efforts to fully comprehend treatment efficacy, potential AEs, and overall health outcomes. Addressing this disparity is not only essential for equitable health care, but also for advancing our understanding of how women and minority populations respond to cardiovascular therapies.

REFERENCES

1. American Heart Association. The Facts about Women and Heart Disease. www.goredforwomen.org. 2019. Accessed May 23, 2024. https://www.goredforwomen.org/en/about-heart-disease-in-women/facts

2. Yong CM, Fearon WF. Underrepresentation of women in revascularization trials. JAMA Cardiol. May 08, 2024. doi:10.1001/jamacardio.2024.0768

3. Gaudino M, Di Mauro M, et al. Representation of women in randomized trials in cardiac surgery: a meta‐analysis. J Am Heart Assoc. August 5, 2021. doi.org/10.1161/JAHA.120.020513

4. Reading between the guidelines: how sex differences impact cardiovascular therapy. Pharmacy Times. June 16, 2023. Accessed May 24, 2024. https://www.pharmacytimes.com/view/reading-between-the-guidelines-how-sex-differences-impact-cardiovascular-therapy

5. Farrero M, Bellumkonda L, Gómez Otero I, Díaz Molina B. Sex and heart failure treatment prescription and adherence. Front Cardiovasc Med. 2021;8:630141. May 7, 2021. doi:10.3389/fcvm.2021.630141