Lack of data collection in clinical trials prevents us from evaluating inclusion of people with disabilities

Objectives: Improving clinical trial inclusivity for diverse populations, including people with disabilities, is crucial. Ethical considerations emphasize the need for trial enrollment to mirror the potential trial users' diversity, yet underrepresentation persists due to direct and indirect exclusions. The purpose of our study was to determine if trial teams collect data on people with disabilities for diversity monitoring purposes. We also examined how they collect disability and report it. Study Design and Setting: We reviewed trial reports for randomized controlled trials published in the UK National Institute of Health Research library from 2016 to 2021. We extracted data on disability, including if, how and when it was collected, who collected it, the measurements used, and the results presented. Results: We extracted data from 407 trial reports. Disability was not collected as a demographic characteristic in any trial. 27% (109/407) collected some disability data for other purposes, eg, eligibility, a measure of functional outcome or serious adverse events. Disability was most commonly assessed through questionnaires (65%; 71/109), clinical assessment (17%; 19/109), and interviews (8%; 9/109). A variety of measures were used to collect disability information. In 109 trial reports, the most common was a measure of cognitive function, the Mini Mental State Examination, which accounted for 15% overall. Conclusion: Disability is not just under recorded or underreported, it is ignored, in trials. As disability is not collected as a demographic characteristic, people with disabilities remain underserved in trials. Given 16% of the global population live with a disability, it is a threat to the generalizability of all trials and risks exacerbating health inequalities of people with a disability.