Diversity and inclusion in clinical trials are crucial to ensuring that scientific advances benefit all communities, including those with different lived experiences, living conditions, and characteristics such as race and ethnicity, age, sex, and sexual orientation. Factors like biological sex, life experiences, unhealthy and health-promoting behaviors, environmental conditions, genetic variation, and underlying medical problems can influence the risk of developing a disease, experiencing long-term health outcomes, and responding to treatment.

Historically, clinical trials have not always recruited participants who represent the individuals most affected by a particular disease or condition. For instance, many clinical trials relied almost exclusively on White study participants, creating gaps in our understanding of diseases and conditions, preventive factors, and treatment effectiveness across populations. These gaps can impede the quality of health care decision making, counseling on ways to reduce risk, optimal treatment responses, and the development of more effective medications or interventions.

Clinicians and researchers should carefully consider the inclusion or exclusion criteria for their clinical trials to ensure the trial’s results are applicable to all groups. For example, a clinical trial excluding participants with high blood pressure or other comorbidities may end up excluding many people over 65 years old, who are more likely to have these conditions. The trial may then underrepresent certain groups in the study and make the results less applicable to groups who may benefit the most from the findings. Thus, diversity and inclusion in clinical trials are critical to advancing scientific knowledge and improving health outcomes for all communities.