Abstract
BACKGROUND: The rising prevalence of fentanyl has complicated buprenorphine (BUP) initiation due to increased risks for precipitated withdrawal. Low-dose initiation (LDI), or "micro-dosing", has been proposed as an alternative to standard-dose initiation (SDI) to improve tolerability and engagement with care. This study aimed to compare inpatient and post-discharge outcomes of LDI versus SDI among patients with opioid use disorder (OUD) undergoing medically managed withdrawal. METHODS: This retrospective cohort study included adults admitted for medically managed OUD withdrawal during two time periods: SDI (February 2020-April 2021) and LDI (May 2021-August 2022). Sociodemographic, clinical, and treatment data were extracted from electronic medical records. Outcomes included inpatient length of stay (LOS), BUP acceptance and discharge dose, transition to rehabilitation, readmissions within one year, BUP refill rates, and outpatient treatment engagement. Analyses included logistic regression and negative binomial regression with adjustment for baseline urine drug screen results. RESULTS: The sample included 184 patients (127 SDI, 57 LDI) with a mean age of 37 years, predominately White N=140 (76.1%) and female. Groups were demographically similar. Inpatient outcomes did not differ in LOS, BUP acceptance, or discharge dose. The LDI group was less likely to transition to rehabilitation (26% vs 48%). LDI was associated with significantly lower odds of readmission within 1 year, while 30-day readmission rates showed a similar directional trend that did not reach statistical significance. Post-discharge BUP refill rates and outpatient attendance rates were similar between groups. CONCLUSIONS: LDI and SDI produced comparable outcomes across most measures, with LDI associated with fewer readmissions over one year. Both approaches appear to be viable strategies in the fentanyl era.