Objective:

To assess disparities in participant populations in neuromuscular disease studies from 2004–2024.

Background:

Equitable access to clinical research is a critical imperative, yet underrepresentation of non-white and non-male individuals remains a widespread issue, leading to a significant lack of diversity in clinical trials. Similarly, individuals at both age extremes are frequently overlooked despite their distinct treatment responses. Awareness of such inequities within neuromuscular disease research has lagged behind other neurological fields. Therefore, improving recognition and understanding of these disparities is crucial to enhance both the quality of care and the generalizability of research findings.

Design/Methods:

We identified interventional and observational studies on neuromuscular diseases initiated between January 1, 2004, and December 31, 2024, using data from ClinicalTrials.gov and PubMed/MEDLINE. Extracted study variables included participant race, ethnicity, sex, age eligibility criteria, mean or median participant age, funding source, start year, and study phase. These data were analyzed to assess temporal trends and disparities in participant race, ethnicity, and age representation.

Results:

 A total of 2,166 studies were screened, with 462 meeting inclusion criteria, encompassing data from 37,131 participants. Most participants were male (61.4%), White (83.5%), and non-Hispanic/Latino (87.6%). While the proportion of studies reporting race and ethnicity increased over time (p < 0.001 and p = 0.001, respectively), the racial and ethnic composition of participants remained unchanged (p = 1).Regarding age accessibility, 37.9% of studies allowed children. Similarly, trial accessibility for older adults was limited. Even in studies with broader age eligibility, mean and median participant ages clustered around midlife, with underrepresentation at both age extremes. Notably, about half of the studies regarding Duchenne muscular distrophy and spinal muscular atrophy excluded participants over 16 and 18 years, respectively.

Conclusions:

Persistent disparities in race, ethnicity, and age representation remain evident in neuromuscular disease clinical research, underscoring the need for more inclusive study designs.