Reporting of high-risk groups in research in U.S. dementia clinical trials: A systematic review

Abstract

Background

Alzheimer's disease and related dementias (AD/ADRD) disproportionately affect Black and Hispanic populations in the U.S. Despite higher prevalence, they remain underrepresented in randomized controlled trials (RCTs). Adequate reporting and representation are essential for understanding disease biology, risk, and treatment response.

Objective

This systematic review examined U.S.-based AD/ADRD RCTs published from 2010–2023 to determine: (1) whether reporting of race and ethnicity has improved, (2) whether reporting is associated with study characteristics, and (3) whether reporting corresponds to greater representation of high-risk populations.

Methods

Following PRISMA guidelines, we searched MEDLINE and Embase for RCTs of pharmacologic, nutraceutical, or procedural interventions in AD/ADRD. Trials were eligible if conducted exclusively in the U.S. between 2010 and 2023. 5428 records were screened and 126 met inclusion criteria. Data extracted included study design, size, funding source, trial phase, and reporting of race/ethnicity.

Results

Of 126 trials, 35.7% did not report race or ethnicity. Among the 64.3% that did, reporting formats varied: 19% reported race and ethnicity separately, 18.3% combined them, 14.3% provided unclear classifications, and 12.7% reported only percent White. Across reporting trials, White participants comprised 71.2–93.3% of samples; minority representation was low. Larger, multi-site, pharmacologic, and industry-funded studies were significantly more likely to report race and ethnicity (p < 0.05). No significant improvement in reporting was observed over time.

Conclusions

Race and ethnicity remain inconsistently reported in AD/ADRD RCTs, and minority representation is low. Standardized reporting and inclusive recruitment strategies are needed to ensure equitable evidence for dementia treatment and prevention.