Despite increasing awareness and policy changes, women remain underrepresented in cardiovascular clinical trials, leading to potential gaps in heart disease care. A recent review underscores the persistent disparity, revealing that only 26% of participants in heart failure trials were women. This underrepresentation challenges the generalizability of trial findings, given known sex-based differences in heart failure characteristics and treatment responses.
Extent of the Enrollment Gap
Analyses of cardiovascular trials continue to reveal significant gender imbalances. One review of 706 studies focusing on heart failure with reduced ejection fraction (HFrEF) showed that female participation remained below 50%, even with gradual increases towards the end of the study period. Another review encompassing 740 cardiovascular trials between 2010 and 2017 found that women constituted only 38.2% of over 860,000 enrolled adults. While representation was better in hypertension and pulmonary hypertension trials, it lagged in trials for arrhythmia, coronary heart disease, acute coronary syndrome, and heart failure.
Government-funded trials and procedural trials showed particularly low female representation compared to multi-sponsor funded trials and lifestyle intervention trials. Although stroke and heart failure trials saw increased female participation from 2013 to 2017, men still predominated overall, emphasizing the need for sustained efforts to achieve gender equity.
Factors Contributing to Underrepresentation
Several factors contribute to the ongoing underrepresentation of women in cardiovascular trials. These include a lack of awareness of trial opportunities, limited access to trial centers, and logistical challenges such as transportation and childcare. Kathryn Lindley, MD, FACC, of Vanderbilt University Medical Center, emphasized that women often face barriers such as lack of health insurance, transportation, and childcare, making it more difficult for them to participate in research studies.
Cultural factors, biases, and communication approaches also play a role. Studies suggest that women are generally less willing to participate in cardiovascular prevention trials due to perceived higher risks. They may also require more time and external input from family or healthcare providers when making decisions about trial participation. Altruistic motivations, such as participating for "the greater good," may be more influential for women than financial incentives.
Addressing the Disparities
Addressing these enrollment gaps requires a comprehensive, multi-pronged approach. This includes ensuring women have opportunities to participate in research, studying how sex and gender interact with cardiovascular health, educating clinicians on the differences in how heart disease affects women, and empowering women to advocate for themselves and seek care when they sense something is wrong. Clinicians need to be well-informed about the ways heart disease may manifest differently in women and actively listen to their female patients' concerns.
