Health Equity

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A Novel Study Quantifies Who is Missing from Cardiovascular Clinical Research

LDI Researchers Analyzed Ethnicity, Race, and Sex‐Specific Population Participation in Clinical Trials

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Clinical research is the foundation of medical advancement, shaping new treatments and therapies that improve health outcomes. However, several large population groups remain underrepresented in clinical trials. The lack of representation from marginalized racial and ethnic groups, women, people with disabilities, LGBTQ+ individuals, and other historically disenfranchised populations raises critical concerns about generalizability, fairness, and trustworthiness of research findings.

LDI Senior Fellows Rachel Kohn, Alisa J. Stephens‐Shields, Alexander C. Fanaroff, Scott D. Halpern, Meghan B. Lane‐Fall and colleagues analyzed randomized clinical trials on cardiovascular disease and risk factors published between 2017 and 2022 to understand and quantify the representation of female, Black, and Hispanic/Latinx populations. The researchers screened about 2,300 trials, identifying 58 that met inclusion criteria, encompassing almost 124,000 total participants.

The researchers grouped the trials by condition of focus and calculated participation-to-prevalence ratios (PPRs) using prevalence data from the American Heart Association. They divided the proportion of the population of interest enrolled in each type of cardiovascular trial by the corresponding proportion of U.S. disease or risk factor prevalence.

The authors found that 19 of 22 of the trial groups that could be analyzed showed underrepresentation of female, Black, and Hispanic/Latinx patients (Figure 1). None of the populations were overrepresented in any group of trials. Specific subgroups were more representative in some trial groups, including female patients in stroke trials, Black patients in hyperlipidemia trials, and Hispanic/Latinx patients in heart failure trials.

Researchers Found Incomplete Trial and Prevalence Data

The study results likely undercount the actual lack of representativeness in the included trials.

Despite National Institutes of Health (NIH) requirements for demographic reporting in clinical trials, among included studies, participants with an unknown race who were not Hispanic/Latinx comprised the second-largest racial group after white.

Among the 58 reviewed trials, only 15 were conducted exclusively in the U.S., while an additional 14 failed to report the U.S. population enrolled. This further hinders generalizability and, given the widespread adoption of trial findings in U.S. clinical practice, is particularly concerning for female, Black, and Hispanic/Latinx patients.

The researchers used the American Heart Association’s Heart Disease and Stroke Statistics 2023 Update for prevalence data and found it incomplete. Additionally, disease prevalence estimates rely on medical diagnoses, which require access to care and may be affected by clinician bias. Without robust prevalence data, policymakers and healthcare administrators struggle to accurately assess disease burden, prioritize funding, and develop targeted improvement strategies.

Moving Toward More Representative Clinical Trials

This is the first study to quantify the failure of cardiovascular clinical research to include female, Black, and Hispanic/Latinx populations, despite recognition that underrepresentation within randomized clinical trials threatens generalizability, reinforces inequities in cardiovascular disease, and may contribute to medical mistrust. To improve representativeness in clinical trials, regulators and payers should enforce policies that ensure adequate enrollment and retention of underrepresented populations.

The study, “Who Are We Missing? Reporting of Ethnicity, Race, and Sex‐Specific Populations in Clinical Trials,” was published December 24, 2024 in the Journal of the American Heart Association. Authors include Rachel Kohn, Dorothy Sheu, Emma Britez Ferrante, Adina Lieberman, Medha R. Maitra, Josiah Drakes, Alisa J. Stephens‐Shields, Alexis K. Okoh, Alexander C. Fanaroff, Alanna A. Morris, Modele O. Ogunniyi, Neal W. Dickert, Scott D. Halpern, and Meghan B. Lane‐Fall.

Author

Christine Weeks

Christine Weeks

Director of Strategic Initiatives

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