
Women Still Underrepresented in Key Cardiovascular Trials
Key Takeaways
- Women are underrepresented in cardiovascular trials, especially in arrhythmia, CHD, ACS, and heart failure studies, as shown by low participation:prevalence ratios.
- Trials in pulmonary hypertension and obesity have higher female representation, reflecting targeted outreach and higher female prevalence in these conditions.
From 2017 to 2023, women were especially underrepresented in trials in arrhythmia, coronary heart disease, acute coronary syndrome, and heart failure.
Women continue to be underrepresented in many
The analysis, published in
Where Gaps Are Largest
Across disease areas, the median female:male (F:M) ratio was lowest in trials focused on:
- Heart failure: 0.51
- Arrhythmias: 0.50
- CHD: 0.39
- ACS: 0.32
When benchmarked against population prevalence, median PPRs were low in trials on:
- ACS: 0.79
- Stroke: 0.74
- CHD: 0.66
On the other hand, trials in
Enrollment also varied by trial characteristics. Women were more likely to be included in studies led by research institutions (F:M, 0.97; PPR, 1.12) than in industry- or government-sponsored trials, which had ratios of 0.57 and 0.34, respectively. Lifestyle intervention trials showed higher female participation (F:M, 1.51) than drug or device studies, and US-based trials generally achieved higher PPRs than studies conducted in Europe or in multiregion global programs. Trials enrolling cohorts 55 years and younger enrolled higher proportions of women than trials with older median ages, reflecting disease states with younger onset among women.
“Drug trials for hypertension and dyslipidemia had comparatively higher enrollment of women, with hypertension drug trials showing a significant upward trend during the COVID-19 pandemic years,” researchers said. “Although device trials are often associated with lower female participation, the proportion of women did not differ significantly across intervention types (drug, device, or lifestyle).”
Using nonparametric trend testing, the investigators did not find a statistically significant overall change in women’s participation from 2017 to 2024 (z = 1.91; P = .06). Notably, however, there was a significant uptick in women’s participation between 2019 and 2022 (PPR, 0.98; z = 3.01; P = .003), driven largely by hypertension trials and coinciding with wider adoption of decentralized or hybrid trial designs utilizing
“The COVID-19 pandemic tested the resilience of trial structures but also spurred innovation,” the authors said. “To our knowledge, this is the first study to document increased women’s participation in CV [cardiovascular] trials during the pandemic.”
Barriers and Levers for Change
According to the authors, these findings highlight both the
“This pattern underscores the need for prioritizing enrollment improvements not only based on PPR but also on disease burden,” they said.1 “Addressing these gaps requires both improved trial inclusion and broader strategies, such as sex- and gender-based education, clinician awareness, and tools like coronary artery calcium scoring for individualized risk.”
They also cataloged intersecting drivers of underrepresentation that span the trial lifecycle:
- Diagnostic and phenotype bias: traditional, male-centric diagnostic paradigms can miss female-predominant phenotypes such as
ischemia with nonobstructive coronary arteries , limiting eligibility3,1 - Reproductive considerations: exclusion of pregnant and lactating individuals and stringent contraception requirements can depress enrollment among women of reproductive age, with industry-sponsored trials particularly constrained by liability concerns
- Age-related exclusions: upper age cutoffs and comorbidity restrictions disproportionately exclude older adults, despite later-life presentation of many cardiovascular conditions in women.
- Socioeconomic barriers:
caregiving responsibilities , transportation, and rigid visit schedules may reduce participation; decentralized and hybrid models appeared to mitigate some of these barriers during the pandemic - Reporting gaps and leadership: fewer than one-third of phase 3 cardiovascular trial publications report sex-stratified outcomes; trials led by female investigators tend to enroll more women, but women remain underrepresented in leadership roles
References
- Rivera FB, Magalong JV, Bantayan NRB, et al. Participation of women in cardiovascular trials from 2017 to 2023: a systematic review. JAMA Netw Open. 2025;8(8):e2529104. doi:10.1001/jamanetworkopen.2025.29104
- Bibbins-Domingo K, Helman A, Dzau VJ. The imperative for diversity and inclusion in clinical trials and health research participation. JAMA. 2022;327(23):2283-2284. doi:10.1001/jama.2022.9083
- Klein HE. Empagliflozin shown to reduce endothelial dysfunction in women with INOCA. AJMC®. September 10, 2025. Accessed September 11, 2025.
https://www.ajmc.com/view/empagliflozin-shown-to-reduce-endothelial-dysfunction-in-women-with-inoca
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