Disparities in Clinical Trial Participation for Hearing Loss Treatment and Cognitive Outcomes in the United States: A Scoping Review.

Abstract

Emerging evidence suggests hearing loss treatment may have a varying impact on modifying the risk of cognitive decline or dementia across different populations. However, it remains unclear whether prior studies have adequately included a diverse range of patient characteristics and dementia risk factors. This study examines participant characteristics in U.S.-based clinical trials investigating associations between hearing aids (HA)/cochlear implants (CI) and cognitive decline. PubMed, Embase, and Cochrane (inception-December 2024). Scoping review following PRISMA-ScR guidelines. Included U.S. trials in peer-reviewed journals on HA/CI and cognitive decline. Participant characteristics were summarized using descriptive statistics and compared to U.S. Census data. Twenty-two studies (RCTs, non-RCTs, single arm and prospective trials) were included (n = 6-977; mean age: 72.0 years; 66.9% male). Twelve studies utilized HA, and 10 utilized CI. Participants were predominantly White (92.1% ± 9.2), with lower representation among Black (5.4% ± 9.5), Asian (0.1% ± 1.4), and Hispanic/Latino (0.05%; SD not calculatable) populations, reflecting the overrepresentation of White participants (Census 75.3%) and the underrepresentation of others (Census: Black 13.7%, Asian 6.4%, Hispanic/Latino 19.5%). Average education (11.3 ± 2.9 years) was comparable to U.S. averages, and hypertension and diabetes rates (67.2% and 20.1%, respectively) were lower than U.S. age-adjusted rates (74.5% hypertension, 33% diabetes). This review of participants characteristics in studies on hearing loss treatment and cognitive decline revealed disparities, particularly in race/ethnicity. Systemic efforts are needed to recruit underrepresented groups to better understand the impact of hearing loss treatment across diverse populations. Bridging these gaps is essential to improving the representativeness of U.S. populations in clinical trials.