Analysis of Age, Race, Ethnicity, and Sex of Participants in Clinical Trials Focused on Eating Disorders

Studies examining the participation of women, minority racial and ethnic groups, and older individuals in clinical trials have demonstrated gaps in inclusion¹; however, to our knowledge, this has not been studied in trials focused on eating disorders (EDs). There are known disparities in ED diagnosis, access to care, and lifetime risk.² For example, people identifying as Hispanic are less likely to receive treatment than individuals from non-Hispanic groups, despite similar prevalence rates.² Beyond access, current evidence-based treatments may not be appropriate for all individuals, and sociodemographic factors associated with outcomes have largely only been evaluated for adults with binge eating disorder (BED).³

Studying diverse populations may affect diagnosis, recommended treatments, and health outcomes. In this study, we examined the sex, racial and ethnic background, and age of participants in ED clinical trials.

In this cross-sectional study, we collected age, sex, race, ethnicity, and primary diagnosis data from ClinicalTrials.gov for completed interventional studies with results (including children and/or adults) from January 1, 2011, to January 1, 2021, using the term eating disorder. The search was conducted on September 5, 2021. We excluded studies conducted outside the United States. Race and ethnicity categories were prespecified by ClinicalTrials.gov.¹ Primary diagnoses were classified as anorexia nervosa (AN), bulimia nervosa (BN), BED, and other. Per the Common Rule, this study did not require institutional review board approval, as it was based on publicly available information. We followed Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cross-sectional studies and used SPSS statistical software version 26 (IBM Corp) for descriptive analyses.

A total of 21 trials met inclusion criteria: 12 (57%) for BED, 7 (33%) for AN, 1 (5%) for BN, and 1 (5%) for other. There were 16 (76%) drug, 4 (19%) behavioral, and 1 (5%) other interventions. All studies reported age, and most included adults only (16 [76%]), with 5 (24%) including both adults and children and none including children only (Table). Three of 4 trials that allowed older adults (ie, ≥65 years) did not enroll any. Five studies (24%) included female participants only, and the remaining trials overrepresented them (3361 of 4016 total participants [83%] vs 52.1% of US population) (Figure).⁴ Thirteen trials (62%) reported race, and 9 (43%) reported ethnicity. Race and ethnicity representation varied by category (Table). Of the 1828 participants with identified race, 52 (3%) were Asian, lower than the proportion of Asian US residents (6%). Likewise, of 1629 participants with identified ethnicity, 213 (13%) were Hispanic, lower than the proportion of Hispanic US residents (19%).

In this analysis of US-based clinical trials for ED during a 10-year period, we found that older adults were not participants, none of the trials focused exclusively on children and adolescents, men were underrepresented, and some racial and ethnic minority groups were underrepresented.

There is awareness of ED among young⁵ and older populations.² However, our findings suggest underrepresentation of these groups in clinical trials for EDs, even though there is federal guidance to increase participation of individuals of all ages.⁶

We found that men were underrepresented overall and among each diagnostic group (Figure), despite prevalence rates of 19% in AN, 19% in BN, and 40% in BED among men.⁴ Although EDs occur more frequently in women, it is important to investigate the causes, treatments, and outcomes across the gender spectrum, including in men.^2,5

Consistent with other studies,¹ some racial groups were underrepresented, notably Asian, Native Hawaiian or Pacific Islander, and American Indian or Alaska Native. Regarding ethnicity, Hispanic/Latino participants were also underrepresented. Our study further supports the need to increase diverse participation in clinical trials overall and specifically in ED studies.

This study was limited to trials registered in ClinicalTrials.gov. Information about participants remains incomplete for some records. However, registries are a good source to understand characteristics of prior trials addressing ED treatments. Racial categories on the registry do not allow for disaggregation of groups, which limits information about racial subgroups.

This study suggests that populations affected by ED are not equitably reflected in clinical trials, particularly children, older adults, men, and some racial and ethnic minority groups. As ED prevention, diagnosis, and treatment may vary among different populations, it is important to address gaps in inclusion.

Accepted for Publication: December 30, 2021.

Published: February 21, 2022. doi:10.1001/jamanetworkopen.2022.0051

Correction: This article was corrected on March 14, 2022, to fix an error in the Figure key.

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2022 Flores LE et al. JAMA Network Open.

Corresponding Author: Julie K. Silver, MD, Department of Physical Medicine and Rehabilitation, Harvard Medical School, 55 Fruit St, Boston, MA 02114 (julie_silver@hms.harvard.edu).

Author Contributions: Drs Burton Murray and Silver had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Drs Burton Murray and Silver are senior authors and contributed equally.

Concept and design: Flores, Burton Murray, Silver.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Flores, Burton Murray, Silver.

Critical revision of the manuscript for important intellectual content: All authors.

Administrative, technical, or material support: Flores, Muir.

Supervision: Burton Murray, Silver.

Conflict of Interest Disclosures: Dr Silver reported receiving grants from the Binational Scientific Foundation and being a venture partner at Third Culture Capital outside the submitted work. Dr Burton Murray reported receiving royalties from Oxford University Press. No other disclosures were reported.

Funding/Support: This manuscript was supported by the National Institute of Diabetes and Digestive and Kidney Diseases, K23 DK131334, to Dr Burton Murray.

Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.