Clinical trials are the cornerstone of medical progress. They test new treatments and therapies, giving hope to patients and advancing healthcare for everyone. But who gets to participate in these crucial studies? And are the participants truly representative of the people most affected by the diseases being studied? A recent scientific commentary published in Nature argues that the way we often measure representation in clinical trials might be flawed, potentially hiding crucial disparities.
The Old Way: Using the Census for Representation
Imagine a large study testing a new drug for a specific type of cancer. To see if the study includes a fair mix of people, researchers often compare the racial and ethnic makeup of the trial participants to the overall U.S. population, using data like the Census. This approach was used in a large analysis of nearly 3,000 clinical trials conducted between 2008 and 2019. That analysis concluded that some groups, like Black and Native Hawaiian/Other Pacific Islander (NHPI) participants, were actually “overrepresented” in many trials compared to their numbers in the 2010 Census, while others like women, American Indian/Alaska Native (AI/AN), Asian, White, and multi-racial individuals were underrepresented.
While comparing trial participants to the general population seems logical at first glance, the authors of this new commentary point out a critical flaw: it doesn’t consider how common a specific disease is within different groups.
A Better Way: Focusing On Who Is Most Burdened by the Disease
Diseases don’t affect everyone equally. Some conditions are much more common in certain racial or ethnic groups than others. For example, if a disease disproportionately affects Black individuals, simply comparing trial participation to the overall U.S. population might wrongly suggest Black participants are “overrepresented”. In reality, their participation might still be too low compared to the actual need for the treatment within their community.
The commentary argues strongly for a different approach: comparing trial representation to the disease incidence – the rate at which new cases of the specific disease occur within each population group. This “incidence-based” approach gives a much clearer picture of whether a trial truly includes the populations most burdened by the condition being studied. Several researchers and studies are already advocating for and using this method, particularly in cancer research.
Accurate measurement matters
Getting representation right isn’t just about numbers; it’s about being equitable. If trials don’t include enough people from the groups most affected by a disease, we might not know if a new treatment works well for them. Concluding that certain groups are “overrepresented” based on flawed comparisons could unintentionally lead researchers to recruit fewer participants from those communities in the future, worsening existing health disparities.
“By overlooking disease-specific incidence, the actual need for disease-targeted interventions across different racial and ethnic groups remains unaccounted for,” the researchers write.
The commentary also highlights that using only the 2010 Census data to evaluate trials spanning over a decade (2008-2019) doesn’t account for the changing diversity of the U.S. population during that time.
Building trust is another crucial factor. Ensuring that trials reflect the populations they aim to serve can help build confidence in medical research within communities that have historically been marginalized or mistreated. Meaningful representation, especially ensuring enough participants from minority groups disproportionately affected by a disease, is vital for fairness and producing robust scientific results.
Moving Forward
The authors commend the original study for its comprehensive scope and for including often-overlooked groups like AI/AN and NHPI populations. They agree with the fundamental goal of achieving equitable representation in clinical trials.
However, they urge the research community to move beyond simple Census comparisons. By adopting disease incidence as the benchmark for representation and setting enrollment goals accordingly, we can ensure clinical trials are truly equitable. This means actively collecting the data needed to understand disease burden across different groups and designing trials that meaningfully include all communities, ultimately leading to better and fairer healthcare for everyone.
