Clinical trials often exclude people with intellectual disabilities

What are the main findings you uncovered in your most recent research related to adults with intellectual disability and their participation in research trials?

We had two major findings.

The first is that when we looked for clinical trial eligibility criteria that would signal the potential inclusion of adults with intellectual disability (e.g., plans for accommodations for those with low literacy, inclusion of individuals with legally appointed guardians), we rarely found them.

Second, we found that almost three-quarters of all clinical trials have eligibility criteria that can easily result in the exclusion of adults with intellectual disability. These studies had two primary paths that can lead to exclusion.

About one-third of the clinical trials have eligibility criteria that directly excludes individuals with intellectual disability or cognitive impairment based on their diagnosis or legal capacity to provide consent; and about two-thirds of clinical trials have eligibility criteria excluding individuals who might not be able to read or write, lack such functional skills as self-care skills, or the ability to read and write, do not have access to technology, or who, in the view of the research team, are unable to complete study procedures, safely engage in the research, have the necessary health status, or may otherwise confound study findings.

These are exclusion criteria that adults with intellectual disability may be more [affected] by due to systemic oppression and other social factors.

From both a scientific and ethical standpoint, why is it necessary to include this population—as well as other underrepresented groups—in clinical research trials?

Although largely invisible in public health surveillance and the ongoing efforts to monitor the well-being of a population, adults with intellectual disability are a health disparities population.

They experience disparities in social determinants of health—such environmental conditions as where people live and their access to education, health care, and economic opportunities that drive health outcomes—have increased risk for chronic conditions, and experience unmet health needs.

Via the development of ways to detect, diagnose, treat, and prevent diseases, clinical trials improve the health and well-being of individuals and populations. When we have representation from all segments of society, we can best ensure all people benefit from ensuing discoveries.

Persistent and widespread exclusion and underrepresentation from clinical trials means clinicians may not know whether a particular medication or treatment is safe and effective for their patients.

Full representation in clinical trials is thus a step towards health equity and is rightly encouraged, and sometimes mandated, by federal agencies funding health research. The National Institutes of Health (NIH), for example, has a dedicated program—the INCLUDE Project—to advance the inclusion of individuals with Down syndrome in clinical trials. Ethically, it’s also important to foster inclusive societies and conditions that nurture health equity.

Was there anything that surprised you about this work, or a finding that you didn’t expect when you first started?

Two of our findings surprised us.

First, we often see study protocols that exclude individuals based on consent capacity. However, in our study, we saw less of this type of exclusion than we predicted (though still more than desirable). This finding was surprising in a good way—it does appear that to some extent researchers are moving away from the ethically problematic approach of categorical exclusion of populations based on diagnostic labels.

This finding may reveal that researchers are better understanding that categorical exclusion can be discriminatory and does not reflect contemporary approaches to the inclusion of diverse populations in health research that favor responsible inclusion and practices that are sensitive to contextual features such as risks.

We were, while perhaps not necessarily surprised, profoundly concerned that we frequently saw broad eligibility criteria that lacked ethical or scientific justification and allowed research staff to use their discretion, rather than standardized assessment, to exclude people.

Examples of such approaches allowed research staff to use their description to discern who might be unable to complete study procedures, safely engage in the research, have the necessary health status, or may otherwise confound study findings. This finding is troubling as these vague, catch-all categories without guidelines or clear assessment procedures for staff decision-making readily allow ableism (discrimination on the basis of disability) to creep into determinations of eligibility.

What solutions are there to address this ongoing health practice disparity?

There are ways to responsibly address the ethical, policy, and practical dilemmas that emerge from including adults with intellectual disability in clinical trials. We need to help researchers see the strengths and abilities of adults with intellectual disability and have the skills to interact effectively and respectfully with them.

One piece of this involves enhancing consent capacity via environmental modifications to increase the understandability of consent materials; this emphasis on accommodations to enable equal access is consistent with federal laws.

Another piece involves meaningful assent procedures when someone does have a legally appointed guardian. A third piece requires rigorous scrutiny of eligibility criteria and their assessment so that criteria are appropriately justified and assessed via standardized processes.

Federal agencies can play critical roles in achieving such outcomes by supporting policies that require representation and providing funding levels and capacity-building opportunities that provide researchers the necessary resources and skills to flexibly include adults with intellectual disability in clinical trials.