How Excluding Disabled Populations from Clinical Trials Impacts Care

Using data from ClinicalTrials.gov, researchers collected data on eligibility criteria from approximately 100 clinical research protocols. Of the 97 interventional studies, 14 focused on dementia, 24 on depression, 34 on diabetes, and 25 on lung cancer. Based on the data collected, researchers deduced that the exclusion of disabled populations is unjustifiable and can impact care.

The researchers in the publication state that over 80% of the publications “permitted substantial latitude to investigators to exclude participants at their discretion.” This observation was accurate for all diabetes studies, 93% of dementia studies, 67% of depression studies, and 76% of trials on lung cancer.

Researchers in the study also found high exclusions rates based on multiple conditions. Chronic conditions — a catchall category — were excluded from 93% of studies. This category did not provide much information. However, psychiatric disorders were excluded in 68% of studies. Other exclusionary criteria included HIV or hepatitis, substance use, cognitive or intellectual impairments, visual impairment, hearing impairment, or mobility issues.

“This mixed-methods review of protocol eligibility criteria supports concerns that people with disabilities are excluded from clinical research. First, 99% of the studies we reviewed required a signed informed consent,” stated researchers in the published article.

The investigators found that these exclusions were typically unjustified. Beyond some ambiguous explanations, some studies lacked a basis altogether.

“Clearly documented scientific or ethical justification should accompany all eligibility criteria. Written justification would provide the opportunity for oversight bodies such as Institutional Review Boards (IRBs) to review these criteria for relevance and necessity and determine whether exclusion can be overcome by the provision of support or other accommodations. Such documentation can facilitate the consistent and appropriate application of eligibility criteria by study teams in screening potential study participants,” recommended researchers in the article.

Discussions around clinical trial diversity often focus on a lack of racial or gender diversity. Disabled populations continue to be excluded from the conversations around inclusivity in medicine. Understanding the rate and lack of justification behind excluding disabled people is essential for knowing how to treat these populations properly. There are currently no guidelines requiring investigators to justify exclusionary criteria. However, this study may incentivize some protocols to be put in place.