Relationship of hub and treatment characteristics with client outcomes in the initial Washington State hub and spoke cohort

Abstract

IntroductionWashington State's Hub and Spoke (HS) approach aims to improve availability of opioid use disorder (OUD) treatment. Washington initially funded six hubs with expertise in medications for opioid use disorder (MOUD) that built care networks with referral and treatment partners (spokes). We assessed outcomes for the initial HS cohort, considering the role of HS and treatment characteristics. MethodsWe conducted a cohort-based observational study using 2017–2019 Medicaid claims data for 2841 HS participants aged 18–64, excluding those with past-month MOUD, in an intent-to-treat analysis. We describe treatment characteristics (MOUD type, treatment setting, and hub type at the initial HS visit, number of outpatient services in their first HS month), and six-month outcomes (MOUD continuity, emergency department (ED) utilization, hospitalization, and intensive SUD treatment). We used multivariable regressions to assess associations with six-month outcomes, adjusting for client characteristics. ResultsTwo-thirds (68 %) of participants received buprenorphine, 22 % methadone, 5 % naltrexone, and 5 % outpatient without MOUD for their initial visit. Within six months, 45 % had an ED visit, 14 % any hospitalization, and 18 % entered intensive SUD treatment. Only 24 % remained on MOUD for six months. Compared to buprenorphine, the methadone sample had higher odds of MOUD continuity (aOR = 2.81, 95%CI 2.21–3.55), and the naltrexone sample had lower odds (aOR = 0.36, 95%CI 0.19–0.66). FQHC/public health treatment settings had higher odds of MOUD continuity (aOR = 1.70, 95%CI 1.17–2.47) but hub type was not significant. MOUD continuity increased with 2+ outpatient services for the buprenorphine sample (aOR range 2.55–4.73). Odds of intensive SUD treatment were lower for the methadone sample, compared to buprenorphine (aOR = 0.16, 95%CI 0.11–0.23), all settings compared to SUD settings (aOR range 0.32–0.58), and SUD + MH and medical/hospital hubs compared to SUD only hubs (aOR range 0.28–0.41). ConclusionsMost participants did not attain six-month MOUD continuity, despite the HS approach, with variations by MOUD type and treatment setting. The number of outpatient services in the first month for buprenorphine clients was associated with greater odds of MOUD continuity and reduced odds of intensive SUD treatment. More work is needed to improve MOUD continuity for people with OUD within the HS model.