System-level factors shaping the implementation of "hub and spoke" systems to expand MOUD in rural areas

Background: Hub and spoke systems (HSS) are increasingly promoted as a systems-level intervention to expand access to medication for opioid use disorders (MOUD), particularly in rural areas with limited treatment options. The HSS model consists of sub-systems in which "hubs" deliver specialized expertise to a regional network of office-based opioid treatment (OBOT) providers in "spokes," who together create a continuum of acute and chronic care. Yet, little is known about system-level factors (e.g., system structure, financing) that influence HSS implementation and sustainability in rural areas. Methods: For this case study, we conducted semi-structured interviews with substance use disorder treatment providers (N = 26) and system-level stakeholders (N = 16) in five rural HSS sub-systems throughout one state. We undertook iterative textual analysis of interview transcripts, identifying and coding themes related to key implementation constructs associated with the Exploration, Preparation, Implementation and Sustainability (EPIS) framework. Results: California policy-makers adopted HSS to expand rural access to opioid treatment programs (OTPs, i.e., providers of methadone and other medications for opioid use disorder). However, stakeholders questioned the model's fit for rural regions featuring few established OTPs that could function as hubs and critiqued its treatment-focused approach, felt to sideline harm reduction service providers. Contracts to serve rural regions were awarded entirely to for-profit methadone providers, contributing to stigma and distrust among many buprenorphine providers whose organizations were later recruited as spokes. While hubs offered financial resources enabling some spokes to expand MOUD, the needs of spokes varied considerably. Relationships between hubs and spokes to facilitate the care continuum under HSS were restricted by limited behavioral health resources and the large distances characterizing rural California. Conclusions: This case study reveals how rural contextual factors such as geography and behavioral healthcare resource availability can dramatically influence differential HSS implementation.