Primary outcome indices in illicit drug dependence treatment research: systematic approach to selection and measurement of drug use end‐points in clinical trials

Abstract

Aims Clinical trials test the safety and efficacy of behavioral and pharmacological interventions in drug-dependent individuals. However, there is no consensus about the most appropriate outcome(s) to consider in determining treatment efficacy or on the most appropriate methods for assessing selected outcome(s). We summarize the discussion and recommendations of treatment and research experts, convened by the US National Institute on Drug Abuse, to select appropriate primary outcomes for drug dependence treatment clinical trials, and in particular the feasibility of selecting a common outcome to be included in all or most trials. Methods A brief history of outcomes employed in prior drug dependence treatment research, incorporating perspectives from tobacco and alcohol research, is included. The relative merits and limitations of focusing on drug-taking behavior, as measured by self-report and qualitative or quantitative biological markers, are evaluated. Results Drug-taking behavior, measured ideally by a combination of self-report and biological indicators, is seen as the most appropriate proximal primary outcome in drug dependence treatment clinical trials. Conclusions We conclude that the most appropriate outcome will vary as a function of salient variables inherent in the clinical trial, such as the type of intervention, its target, treatment goals (e.g. abstinence or reduction of use) and the perspective being taken (e.g. researcher, clinical program, patient, society). It is recommended that a decision process, based on such trial variables, be developed to guide the selection of primary and secondary outcomes as well as the methods to assess them.

Evaluation of medication-assisted treatment of opioid dependence—The physicians’ perspective

“…The overall "moderate" evaluation across the whole sample calls into mind the chronicity and complexity of the treatment of opioid dependence (McLellan et al, 2000). Our findings are of particular interest in light of the debate about which outcome parameters to apply in the assessment of substance use treatment (Bühringer, 2012;Donovan et al, 2012;Miller and Miller, 2009;Tiffany et al, 2012;Uchtenhagen, 2015). Some researchers have argued that substance use is the most suitable parameter for treatment success and should thus be the primary outcome of treatment evaluation (Donovan et al, 2012).…”

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