Assessing Drug Use during Follow-Up: Direct Comparison of Candidate Outcome Definitions in Pooled Analyses of Addiction Treatment Studies

Abstract

Background Selection of appropriate outcome measures is important for clinical studies of drug addiction treatment. Researchers use various methods of collecting drug use outcomes and must consider substances to be included in a urine drug screen (UDS); accuracy of self-report; use of various instruments and procedures for collecting self-reported drug use; and timing of outcome assessments. Objectives We sought to define a set of candidate measures to 1) assess their inter-correlation, and 2) identify any differences in results. Methods Data were combined from completed protocols in the National Institute on Drug Abuse Clinical Trials Network (CTN), with a total of 1897 participants. We defined nine outcome measures based on UDS, self-report, or a combination. Multivariable, multilevel GEE models were used to assess subgroup differences in intervention success, controlling for baseline differences and accounting for clustering by CTN protocols. Results There were high correlations among all candidate outcomes. All outcomes showed consistent overall results with no significant intervention impact on drug use during follow-up. However, with most UDS variables, but not with self-report or “corrected self-report”, we observed a significant gender-ethnicity interaction with benefit shown in African American women, white women, and Hispanic men. Conclusion Despite strong associations between candidate measures, we found some important differences in results. Scientific Significance In this study, we demonstrated the potential utility and impact of combining UDS and self-report data for drug use assessment. Our results suggest possible differences in intervention efficacy by gender and ethnicity, but highlight the need to cautiously interpret observed interactions.

Toward empirical identification of a clinically meaningful indicator of treatment outcome: Features of candidate indicators and evaluation of sensitivity to treatment effects and relationship to one year follow up cocaine use outcomes

“…In addition, there is very little consensus regarding how self-report and urine data should be combined when the two sources of information do not agree: The recommendation “believe the source that indicates use” is sound but difficult to operationalize, particularly for continuous variables (Korte et al, 2011). Consider the case in which a participant reports using no marijuana for 2 consecutive weeks.…”

The National Drug Abuse Treatment Clinical Trials Network Data Share project: Website design, usage, challenges, and future directions

“…The availability of data files from multiple CTN studies not only allows investigators to examine women and minority groups’ ongoing participation and retention in CTN studies, 31 but also helps elucidate gender and racial/ethnic issues in clinical measures, subgroup analysis, polydrug use patterns, comorbidity, and HIV risk behaviors. 19,23,27,28,30,32,33 These findings provide invaluable information to the addiction treatment field and inform further refinement of newer study designs. 23,34 While the costs of maintaining the website are fairly low, the potential benefits of the use of the data are high, and continue to grow as the existing studies continue to be used and data from new studies are added to the website.…”

The Use of Neuromodulation in the Treatment of Cocaine Dependence

“…In drug addiction research, the sensitive nature of the data collected, the tendency to minimize use and its impact, and lack of insight or denial, may lead study participants to misreport their drug use. Conversely, relying on urine drug screens alone may miss drug use events occurring too far in the past to be detected [27]. A good outcome measure should estimate the prognosis accurately.…”