Systematic review of the efficacy, effectiveness, and cost-effectiveness of stepped-care interventions for the prevention and treatment of problematic substance use

Background: Stepped-care is a commonly recommended and implemented care model across health care domains, including substance use. Despite their presumed efficient allocation of treatment resources, a current and robust evidence synthesis is needed on the efficacy, effectiveness and cost-effectiveness of stepped-care for substance use.Methods: This systematic review analyzed articles describing evaluations of stepped-care models that measured the use of acutely psychoactive substances (i.e., alcohol, cannabis, hallucinogens, inhalants, opioids, sedatives, hypnotics, anxiolytics, and stimulants) as a primary or secondary outcome, in participants over 18 years old. The analysis investigated model and participant characteristics associated with treatment outcomes.Results: The study team conducted a search of five databases of literature (PsychINFO, MEDLINE, Embase, Cochrane Library and Scopus) published between January 1, 2010, and November 1, 2020. The search yielded 1051 unique articles, 19 of which were included in the analysis. The studies had considerable variability in sample sizes (n = 18-2310), time to follow-up (4.5 months to 3 years), and retention rates (35.1-100 %). Studies examined outcomes for either alcohol alone (n = 9), alcohol and other drug use (n = 9), or drug use alone (n = 1). Most studies (n = 13;) were rated as good quality. Three (15.8 %) were rated as fair and three (15.8 %) were rated as poor quality. The evidence regarding the efficacy, effectiveness and cost-effectiveness of stepped-care approaches is limited, but four of seven studies found that adaptive-care interventions delivered in the context of other systemic interventions produced greater benefit than control conditions in relation to at least one alcohol-related outcome. We have insufficient evidence to determine whether the modes or intensity of in-terventions included in the models, or decision rules used to step people up or down to differing levels of care, have an impact on outcome.Conclusion: Heterogeneity between studies with regard to model and evaluation design limited the degree to which the analysis could draw robust conclusions. Sample recruitment and statistical power are particular challenges, and the field needs more innovative evaluation designs to assess the efficacy, effectiveness, and cost-effectiveness of stepped-care models.