Analyses: Older Patients Excluded from Many Research Studies
Geriatric patients often are excluded from clinical trials due to age-based exclusion criteria.1,2 Researchers recently analyzed 302 trials with 262,354 participants. They found the median age of trial participants was a mean 6.49 years younger than the median age of the population.3
Age disparities were worse for industry-funded trials; for trials with enrollment criteria restrictions based on age cutoffs or performance status; for trials that evaluated a targeted, systemic therapy; and for lung cancer trials, according to another group of researchers.4 Their analysis of 847 trials on ClinicalTrials.gov revealed older adults were likely to be excluded from more than 50% of COVID-19 clinical trials and 100% of vaccine trials. “Most academic papers and news articles are limited to reporting the problem instead of directly addressing it. What’s missing are solutions,” says Anh Ninh, PhD, an associate professor of computational operations research at William & Mary in Williamsburg, VA.
Ninh and colleagues analyzed data on ClinicalTrials.gov regarding cardiovascular diseases, cancer, and type 2 diabetes studies conducted from 2010-2021. They investigated relevant factors that could be contributing to the exclusion of elderly people from trials.5 “As people age, they are usually subject to concomitant drug treatment, comorbidities, and worsening levels of organ functioning,” Ninh observes.
Cancer trials recorded the lowest percentage of age-capped enrollment, while type 2 diabetes trials were most likely to be age-capped. Cardiovascular trials were more likely to be age-capped than cancer trials. “The results obtained from clinical trials are based on a certain demographic, and they should only be applied confidently to that same group of individuals,” Ninh says.
Researchers also studied whether the funding mechanism (public vs. private) affected the proportion of people excluded from studies. NIH-funded trials include fewer age caps, historically, than trials funded from sources other than NIH. There were no significant changes in the percentage of trials with upper age limits before or after the 2019 NIH Inclusion Across the Lifespan policy was enacted. “Apparently, guidelines are not effective in preventing age exclusion since this issue is still going on,” Ninh notes.
Notably, this work was hindered somewhat by lack of detailed data. “Companies do not report the number of patients in certain age groups,” Ninh explains.
The only available information on ClinicalTrials.gov is the age cap for trials. Adverse events reported by age group after drugs are approved should be collected and made available on ClinicalTrials.gov, according to Ninh. “Only with more detailed data can we investigate this problem more deeply and come up with better solutions,” Ninh offers.
- van Marum RJ. Underrepresentation of the elderly in clinical trials, time for action. Br J Clin Pharmacol 2020;86:2014-2016.
- Sedrak MS, Freedman RA, Cohen HJ, et al. Older adult participation in cancer clinical trials: A systematic review of barriers and interventions. CA Cancer J Clin 2021;71:78-92.
- Ludmir EB, Mainwaring W, Lin TA, et al. Factors associated with age disparities among cancer clinical trial participants. JAMA Oncol 2019;5:1769-1773.
- Helfand BKI, Webb M, Gartaganis SL, et al. The exclusion of older persons from vaccine and treatment trials for coronavirus disease 2019 - Missing the target. JAMA Intern Med 2020;180:1546-1549.
- Nguyen D, Mika G, Ninh A. Age-based exclusions in clinical trials: A review and new perspectives. Contemp Clin Trials 2022;114:106683.
Investigators learned age disparities were worse for industry-funded trials; for trials with enrollment criteria restrictions based on age cutoffs or performance status; for trials that evaluated a targeted, systemic therapy; and for lung cancer trials.
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