Examining cocaine use reductions and long-term outcomes in two clinical trials of continuing care for cocaine dependence

Victoria R Votaw; Felicia R Tuchman; Corey R Roos; Hanna M Hebden; James R McKay; Brian D Kiluk; Katie Witkiewitz

doi:10.1016/j.josat.2024.209394

Examining cocaine use reductions and long-term outcomes in two clinical trials of continuing care for cocaine dependence

J Subst Use Addict Treat. 2024 May 11:163:209394. doi: 10.1016/j.josat.2024.209394. Online ahead of print.

Authors

Victoria R Votaw¹, Felicia R Tuchman², Corey R Roos³, Hanna M Hebden⁴, James R McKay⁵, Brian D Kiluk³, Katie Witkiewitz⁴

Affiliations

¹ Department of Psychology, University of New Mexico, Albuquerque, NM, United States of America; Center on Alcohol, Substance use, And Addictions (CASAA), University of New Mexico, Albuquerque, NM, United States of America; Department of Psychiatry, Harvard Medical School, Boston, MA, United States of America; Division of Depression and Anxiety Disorders, McLean Hospital, Belmont, MA, United States of America. Electronic address: vvotaw@mclean.harvard.edu.
² Department of Psychology, University of New Mexico, Albuquerque, NM, United States of America.
³ Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States of America.
⁴ Department of Psychology, University of New Mexico, Albuquerque, NM, United States of America; Center on Alcohol, Substance use, And Addictions (CASAA), University of New Mexico, Albuquerque, NM, United States of America.
⁵ Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States of America; Center of Excellence in Substance Addiction Treatment and Education (CEASATE), Corporal Michael J. Crescenz Philadelphia VA Medical Center, Philadelphia, PA, United States of America.

PMID: 38735481
DOI: 10.1016/j.josat.2024.209394

Abstract

Background: There is a need to identify clinically meaningful non-abstinent endpoints for cocaine use disorder (CUD) clinical trials. In this study, we sought to replicate and extend prior work validating reductions in cocaine use frequency levels as an endpoint by examining associations between reductions in cocaine use frequency and long-term functioning outcomes.

Methods: We conducted a secondary analysis of two randomized clinical trials (N = 445; 77.5 % male; mean age = 42.18 years; 86.5 % Black, 10.8 % non-Hispanic white) that evaluated telephone-based continuing care for a 12- and 24-month period. Cocaine use frequency levels, measured with the Timeline Followback, were (1) abstinence (no past-month cocaine use), (2) low-frequency use (1-4 days of use/month), and (3) high-frequency use (5+ days of use/month).

Results: Among those who completed the 12-month follow-up (n = 392), most reduced from high-frequency use at baseline to abstinence at the 12-month follow-up (n = 243; 62.0 %). An additional 21.2 % (n = 83) reported either high-to-low-frequency use (n = 35; 8.9 %) or low use-to-abstinence (n = 48; 12.2 %); 16.8 % of participants (n = 66) did not change or increased their cocaine frequency level. Compared to those who had no change/increases in frequency levels, at least a one-level reduction from baseline to 12-month follow-up (i.e., high-to-low-frequency use, high-to-abstinence, low-to-abstinence) was concurrently associated with lower levels of negative consequences at the 12-month follow-up and prospectively with lower levels of cocaine use and consequences at 24-month follow-up, with effect sizes in the medium-to-large range. Those who reduced to abstinence generally had fewer drug use consequences at the 12-month follow-up than those who reduced to a low-frequency level; however, these groups did not significantly differ on any outcomes at the 24-month follow-up.

Conclusions: Categorical reductions in cocaine use frequency levels, including those short of abstinence, are associated with less cocaine use and lower problem severity up to two years following treatment entry. Low-frequency cocaine use following the initial treatment phase does not appear to forebode worsening functioning, such as escalations in cocaine use.

Keywords: Cocaine use disorder; Endpoints; Harm reduction; Non-abstinence endpoints.