Insights from system dynamics applications in addiction research: A scoping review.

BACKGROUND AND AIMS: Substance misuse and use disorders are dynamic and complex problems, situated within systems of interacting social, environmental, and neurobiological factors. System dynamics (SD) methods broaden, test, and improve understanding of complex systems and can help inform effective action. We sought to systematically review the use of SD tools in addiction-related research. METHODS: Following PRISMA guidelines, we searched several databases from 1958 to 2019. We included studies focused on addiction-related screening and diagnosis, treatment, and return to use, as well as studies focused on earlier stages that may begin a path to addiction (e.g., experimentation, misuse onset). RESULTS: We extracted information from 59 articles with a median publication year of 2014. In addition to using SD to understand the underlying complexity driving addiction-related trends, other commonly cited reasons for use of SD included assessing impacts of potential actions (n = 35), predicting future trends (n = 28), and supporting strategic planning processes (n = 22). Most studies included simulation models (n = 43); however, some presented insights from qualitative SD diagrams (n = 9) and concept models (n = 6). The majority of studies focused on stages leading to potential addiction: initiation/ experimentation (n = 42) and misuse onset (n = 38). One-third (n = 20) engaged persons with lived experience or other stakeholders during the modeling process. CONCLUSIONS: Addiction-related SD research has increased over the last few decades with applications varying in several ways, from model purpose and types of data used to stakeholder involvement. Future applications should consider the benefits of stakeholder engagement throughout the modeling process and expanding models to include concomitant substance use.

A mixed methods study of provider factors in buprenorphine treatment retention.

BACKGROUND: Low retention is a persistent challenge in the delivery of buprenorphine treatment for opioid use disorder (OUD). The goal of this study was to identify provider factors that could drive differences in treatment retention while accounting for the contribution of patient characteristics to retention. METHODS: We developed a novel a mixed-methods approach to explore provider factors that could drive retention while accounting for patient characteristics. We used Medicaid claims data from North Carolina in the United States to identify patient characteristics associated with higher retention. We then identified providers who achieved high and low retention rates. We matched high- and low-retention providers on their patients' characteristics. This matching created high- and low-retention provider groups whose patients had similar characteristics. We then interviewed providers while blinded to which belonged in the high- and low-retention groups on aspects of their practice that could affect retention rates, such as treatment criteria, treatment cost, and services offered. RESULTS: Less than half of patients achieved 180-day treatment retention with large differences by race and ethnicity. We did not find evidence that providers who achieved higher retention consistently did so by providing more comprehensive services or selecting for more stable patients. Rather, our findings suggest use of "high-threshold" clinical approaches, such as requiring participation in psychosocial services or strictly limiting dosages, explain differences in retention rates between providers whose patients have similar characteristics. All low-retention providers interviewed used a high-threshold practice compared to half of high-retention providers interviewed. Requiring patients to participate in psychosocial services, which were often paid out-of-pocket, appeared to be especially important in limiting retention. CONCLUSION: Providers who adopt low-threshold approaches to treatment may achiever higher retention rates than those who adopt high-threshold approaches. Addressing cost barriers and systemic racism are likely also necessary for improving buprenorphine treatment retention.