Systematic Review and Meta-Analysis: Reporting and Representation of Race/Ethnicity in 310 Randomized Controlled Trials of Attention-Deficit/Hyperactivity Disorder Medications

Objective

To evaluate the reporting of race/ethnicity data in randomized controlled trials (RCTs) of attention-deficit/hyperactivity disorder (ADHD) medications. Secondary objectives were to estimate temporal trends in the reporting, and to compare the pooled prevalence of racial/ethnic groups in RCTs conducted in the US to national estimates.

Method

We drew on, adapted, and updated the search of a network meta-analysis by Cortese et al. (2018) up to March 2022. We calculated the percentage of RCTs reporting data on race/ethnicity of participants in the published article or in related unpublished material. Temporal trends were estimated with logistic regression. The pooled prevalence of each racial/ethnic group across US RCTs was calculated using random-effects model meta-analyses.

Results

We retained 310 RCTs (including 44,447 participants), of which 231 were conducted in children/adolescents, 78 in adults, and 1 in both. Data on race/ethnicity were reported in 59.3% of the RCTs (75% of which were conducted in children/adolescents and 25% in adults) in the published article, and in unpublished material in an additional 8.7% of the RCTs. Reporting improved over time. In the US RCTs, Asian and White individuals were under- and overrepresented, respectively, compared to national estimates in the most recent time period considered.

Conclusion

More than 30% of the RCTs of ADHD medications retained in this review did not include data on race/ethnicity in their published or unpublished reports, and more than 40% in their published articles, even though reporting improved over time. Results should inform investigators, authors, editors, regulators, and study participants in relation to efforts to tackle inequalities in ADHD research.

Plain language summary

A systematic review of 310 randomized controlled trials for attention-deficit/hyperactivity disorder (ADHD) medications found that race/ethnicity were reported in only 30% of trials. Compared to national estimates, Asian individuals were underrepresented and non-Hispanic Whites individuals were overrepresented, drawing attention to the inequities in participation in ADHD research.

Diversity & Inclusion Statement

One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. We actively worked to promote sex and gender balance in our author group. While citing references scientifically relevant for this work, we also actively worked to promote sex and gender balance in our reference list. While citing references scientifically relevant for this work, we also actively worked to promote inclusion of historically underrepresented racial and/or ethnic groups in science in our reference list.

The author list of this paper includes contributors from the location and/or community where the research was conducted who participated in the data collection, design, analysis, and/or interpretation of the work.

Study preregistration information

Reporting and representation of race/ethnicity in double blind randomised controlled trials of medications for ADHD; https://osf.io/; hfgz8.