How to Make Clinical Trials More Diverse and Inclusive

Clinical Researcher—April 2022 (Volume 36, Issue 2)


Contributed by Florence Healthcare


Many medical professionals worry about a lack of representation in clinical trials, and this lack can have medical consequences. A 2014 study showed that around 20% of new drugs approved between 2008 and 2013 had different effects depending on a person’s race or ethnicity.

In spite of this, many clinical trials in the U.S. still don’t have participant pools that accurately reflect the demographics of the people who will use the drug.

If clinical trials truly wish to be patient-centered, they must include all patients; but how can organizations in the clinical research industry increase the diversity of their trial participants? Further, will the move toward decentralized trials increase diversity or make health disparities worse?

We believe that decentralized trials play an important role—but not the only role—in increasing diversity and inclusion. Research sites, contract research organizations (CROs), and sponsors must combine decentralized technology with an understanding of historical inequities and community outreach if they truly want to increase the diversity of their clinical trials.

Underrepresentation and Patient Recruitment in the U.S.

Recruiting enough patients often presents a problem for clinical trials in the United States. Joseph Munda of First Analysis notes that around 50% of research sites have to extend their recruitment periods, and 37% of sites fail to meet their recruitment targets.

Even when clinical trials succeed in finding enough participants, those participants often don’t reflect the population the research is meant to serve. A special feature in a 2020 issue of ACRP’s Clinical Researcher journal mentions that 13.4% of the U.S. population is Black versus only 5% of trial participants. The disparity is worse for Latinx people, who make up 18% of the population and 1% of trial participants.

In 2021, JAMA published an article on the demographics of vaccine clinical trials from July 2011 to June 2020. This chart shows how the demographics of those vaccine trials compare to the demographics of the U.S. as a whole:

These numbers show that White people were vastly overrepresented in vaccine clinical trials, while Asian people were almost accurately represented. Black, Hispanic, and Indigenous people were underrepresented, and the disparity was most severe for the Black and Hispanic communities.

Other vulnerable groups are underrepresented in clinical trials as well. Clinical trials often don’t track whether they’re including LGBTQ+ people, and people 65 and older were underrepresented in COVID-19 vaccine trials, even though that population was especially vulnerable to the disease.

For vaccines to be effective, they need to be tested on people of many ages, gender identities, races, and ethnicities. However, vaccine clinical trials, like clinical trials in general, do not yet accurately reflect the U.S. population.

How to Improve Representation

Genetics, race, age, gender, weight, and geographic location can all influence whether medical treatments are effective for a specific person. The rise of precision medicine—therapies designed to target specific genes—makes including diverse participants even more important.

So how do we make clinical trials more representative of the population they’re meant to serve?

Dr. Yella Hewings-Martin suggests in her article for Medical News Today that the lack of diverse participants in trials has many causes, from preexisting health inequities to limited access and distrust of medical research. The U.S. Food and Drug Administration (FDA) has also discussed how inclusion/exclusion criteria and difficulty reaching research sites can cause a lack of diversity.

It’s hard to list every factor that could lead to clinical trials not being diverse enough, but we’ve compiled four that we believe have solutions: lack of access to sites, insufficient time and money to participate in studies, overly stringent study inclusion criteria, and patients not feeling represented by the researchers conducting the trial.

As discussed in the sections to follow, some of these problems can be solved by technology, while others require a more comprehensive approach.

Increase Access

Decentralized technology can help a wider range of people take part in clinical trials. According to Dr. Pamela Tenaerts, Chief Scientific Officer for Medable, 70% of people live more than two hours from a major research site. Sean Lynch, Director of Study Operations at TrialSpark, claims that “50% of FDA trials in the U.S. are conducted in only 1% to 2% of ZIP codes.”

Patients who live in rural or underserved areas may be left out of clinical trials because the research site doesn’t reach out to them or because they can’t drive to the site. This leads to a less diverse patient population from which researchers can recruit.

Decentralized clinical trials (DCTs) can help with this problem, since they can take place anywhere. Some DCTs let patients visit clinics and pharmacies close to where they live, while others let patients submit all their data remotely through apps, telehealth visits, or wearable devices. Amir Lahav advocates for this type of remote trial technology on an episode of our podcast.

Michelle Shogren, Senior Director of Innovation at Bayer, also emphasizes the importance of “choose-your-own-adventure” clinical trials personalized to the patient. “Somebody who might have a hard time getting away from work or who lives a long distance from the site might say ‘I would like to have more video visits and home nursing instead of having to come here all the time,’” she points out.

Still, decentralized technology alone won’t guarantee diversity. Research sites, sponsors, and CROs need to consider other factors as well.

Account for Socioeconomic Factors

Distance isn’t the only reason people don’t sign up for clinical trials. Some people can’t pay the associated healthcare costs, and others can’t take time off work or pay for childcare.

For clinical trials to be truly inclusive, they need to be affordable. Technology vendors and research sites don’t have the ability to offset all costs for patients, but they do have the ability to help hourly workers and parents. More people can participate in clinical trials if they can check in on their phone or computer while they’re at work or at home.

Allowing check-ins at local doctor’s offices or pharmacies can also help patients in low-income or rural areas. Michelle Shogren notes that technology can help doctors in these communities serve their patients better by quickly looking up clinical trials for patients who may not have realized trials are available.

However, as Leslie Byatt, Clinical Research Manager for the New Mexico Cancer Care Alliance and University of New Mexico Comprehensive Cancer Center, pointed out when she joined us on our podcast, not every patient has access to WiFi, a computer, or a phone. Patients who can’t afford the Internet may not be able to afford a car either, so they need to receive treatment at places they can reach on foot or by public transport, like the doctors’ offices that Shogren mentioned.

Rethink Trial Exclusion and Inclusion Criteria

Investigators must set inclusion and exclusion criteria to run safe, effective clinical trials. However, the FDA has urged research sites, CROs, and sponsors to think carefully about how they set inclusion criteria to make sure they aren’t excluding potential participants for the wrong reasons.

The FDA has observed that the elderly, people who are overweight, and people who have disabilities or chronic illnesses are sometimes excluded from Phase III or Phase IV trials when they could provide valuable insight into how the drug works for people like them. The investigator must use his or her professional judgment to decide when inclusion criteria can and can’t be expanded, but loosening overly strict criteria may make trials more diverse.

The FDA also notes that people can be unintentionally excluded because they need accommodations to participate in a trial. For example, the 2016 census showed that roughly 13% of the U.S. population spoke Spanish at home, and that number keeps growing. Research sites may be able to recruit more Latinx trial participants if they employ Spanish speakers and offer informed consent forms in Spanish.

Make Participants Feel Represented and Welcome

Some diverse patients might not want to participate in clinical trials because they don’t trust the medical research industry. DCTs can alleviate this feeling by letting participants visit local doctors and pharmacists they already trust.

In the meantime, what if patients don’t have a healthcare provider or need to interact with clinical research staff? Research sites can build trust between participants and their staff by ensuring they have a diverse workforce. Patients may be more likely to participate in clinical research if they see themselves represented among the people running the trial.

Community outreach can also help patients feel like their needs and wants are being considered. Some research sites have started reaching out to patients by speaking at local community centers or houses of worship. Programs like these can show that researchers care about patients’ questions and concerns.


To ensure patients receive the safest, most effective treatments, clinical trials in the U.S. need to recruit diverse participants who accurately represent the population. This can mean using decentralized trials to work with patients in the areas where they live, but it can also mean rethinking exclusion criteria, building a diverse workforce, and establishing trust between research professionals and participants.

To learn more about enhancing representation in clinical trials, check out our eBook on DCTs for research sites and our CEO’s article for the Forbes Tech Council about representation, equity, and inclusion.