Addiction treatment trials: how gender, race/ethnicity, and age relate to ongoing participation and retention in clinical trials

Jeffrey E Korte¹, Carmen L Rosa², Paul G Wakim², Harold I Perl^2
1Division of Biostatistics and Epidemiology, Medical University of South Carolina, Charleston, SC, ²Center for the Clinical Trials Network, National Institute on Drug Abuse, Bethesda, MD, USA

Introduction: Historically, racial and ethnic minority populations have been underrepresented in clinical research, and the recruitment and retention of women and ethnic minorities in clinical trials has been a significant challenge for investigators. The National Drug Abuse Treatment Clinical Trials Network (CTN) conducts clinical trials in real-life settings and regularly monitors a number of variables critical to clinical trial implementation, including the retention and demographics of participants.
Purpose: The examination of gender, race/ethnicity, and age group differences with respect to retention characteristics in CTN trials.
Methods: Reports for 24 completed trials that recruited over 11,000 participants were reviewed, and associations of gender, race/ethnicity, and age group characteristics were examined along with the rate of treatment exposure, the proportion of follow-up assessments obtained, and the availability of primary outcome measure(s).
Results: Analysis of the CTN data did not indicate statistical differences in retention across gender or race/ethnicity groups; however, retention rates increased for older participants.
Conclusion: These results are based on a large sample of patients with substance use disorders recruited from a treatment-seeking population. The findings demonstrate that younger participants are less likely than older adults to be retained in clinical trials.

Keywords: addiction treatment, age, ethnic minorities, gender difference, substance use disorders, race, recruitment, retention, clinical trials