A meta-analysis of cocaine use disorder treatment effectiveness
Authors: Bentzley Brandon S , Han Summer S , Stein Sherman C , Neuner Sophie , Humphreys Keith , Kampman Kyle M , Halpern Casey H 
Published: June 2020

Background

In both the U.S. and U.K., after a period of decline, prevalence of cocaine use has been increasing since 2012 and is now the second leading cause of overdose death from an illicit drug. However, psychosocial treatments for cocaine use disorders are limited, and no pharmacotherapy is approved by regulatory bodies in the U.S. or Europe. We performed a comprehensive meta-analysis to assess treatments’ impacts on cocaine use.

Methods

We performed a meta-analysis of clinical trials that included the word ‘cocaine’ in the title and were published between 31/12/1995 and 31/12/2017. All studies of outpatient adults with active cocaine use and reporting urinalysis results were included. Treatment approaches were clustered into 11 categories. Missing data were imputed using multiple imputation by chained equations. We calculated intention-to-treat log-odds ratios (OR) for the change in proportion of patients testing negative for cocaine at the end of each study and performed multivariate mixed-effects meta-regression. This study was prospectively registered on covidence.org on 31/12/2015, study 8731.

Findings

One hundred fifty-seven studies with 15,842 participants were included. Only contingency management was significantly associated with increased odds of testing negative for cocaine (OR of 2.13, 95% CI 1.62-2.80) and remained significant after all sensitivity analyses.

Interpretation

This meta-analysis is unique in its broad inclusivity of treatment types and trial designs over a two-decade period of investigation. Our results converge with focused meta-analyses on treatments for cocaine use disorders; thus, research efforts and policy changes that expanded implementation of contingency management programs are expected to reduce cocaine use in active users and the associated individual, community, and societal burdens associated.

Funding

None

Panel

Evidence before this study

Before undertaking this study, we examined all cocaine use disorder treatment reviews in Cochrane Collaboration as well as all meta-analyses indexed on PubMed (search term = “cocaine” and article type = Meta-analysis). We identified meta-analyses of several treatments for cocaine use disorders that were negative or indeterminant, including anticonvulsants, antidepressants, antipsychotics, acupuncture, disulfiram, dopamine agonists, opioids, and psychostimulants. Meta-analyses of psychosocial interventions showed variable effect sizes with large heterogeneity between approaches. Meta-analyses of contingency management indicated efficacy in reducing cocaine use, but these have been limited to specific subpopulations or to controlled studies. We expanded our scope beyond prior investigations to comprehensively assess all treatment categories simultaneously across all study types with the aim of increasing our sensitivity for detecting an effective treatment for cocaine use disorders in an otherwise largely negative evidence base.

Added value of this study

Our findings indicate robust effectiveness of contingency management approaches in reducing cocaine use. Other treatment categories were either negative or failed sensitivity testing. This finding highlights the inaccuracy of the common notion that there is no effective treatment for cocaine use disorder.

Implications of all the available evidence

Based on our study, contingency management is an effective treatment for cocaine use disorder. Cocaine use and its associated adverse effects could be significantly reduced in patients suffering from cocaine use disorder through expanded implementation of contingency management programs.