A Retrospective Analysis of Serious Adverse Events and Deaths in US-Based Lifestyle Clinical Trials for Cognitive Health

This retrospective analysis assessed the serious adverse events and deaths reported in lifestyle clinical trials designed to enhance cognitive health in older adults living in the United States. Data was collected from studies conducted between January 1, 2000, and July 19, 2023, using the ClinicalTrials.gov application programming interface. Our query revealed that 76% of these studies did not report trial results. The remaining studies with reported results were categorized under one of four intervention types: Cognitive/Behavioral, Exercise/Movement, Diet/Supplement, and Multi-modal. When all trial types are considered together, the results indicate that lifestyle clinical trials are safe, with no significant increase in relative risk of experiencing an SAE in an intervention group over a control group. And although the increase in relative risk of death in an intervention group over a control group was significant at 28% (X(2) (1, N = 36), p < 0.00688), the probability of death was not higher than the U.S. mortality rates by age. When assessing the data using intervention type, Diet/Supplement trials and Multi-modal trials both had an increase in relative risk of experiencing an SAE in the intervention over the control group, with Diet/Supplement trials at 16% (X(2) (1, N = 2), p < 0.0263) and Multi-modal trials at 365% (X(2) (1, N = 5), p < 0.000213). The Diet/Supplement trials also had an increased risk of death at 67% (X(2) (1, N = 2), p < 0.000197). These results should be taken with careful consideration. Due to such a low reporting rate, the 36 studies included in this analysis do not accurately represent the majority of lifestyle clinical trials conducted in the U.S. This study is valuable in that it highlights the importance of reporting clinical trial results, which will improve transparency in trial results and allow for more accurate assessments of safety in the growing field of cognitive aging and lifestyle interventions for older adults.