Prior use of medications for opioid use disorder in ED patients with opioid overdose: prevalence, misuse and overdose severity

Objectives: Medications for opioid use disorder (MOUD) reduce opioid overdose (OD) deaths; however, prevalence and misuse of MOUD in ED patients presenting with opioid overdose are unclear, as are any impacts of existing MOUD prescriptions on subsequent OD severity. Methods: This was a prospective observational cohort of ED patients with opioid OD at two tertiary-care hospitals from 2015 to 19. Patients with confirmed opioid OD (via urine toxicology) were included, while patients with alternate diagnoses, insufficient data, age < 18, and prisoners were excluded. OD severity was defined using: (a) hospital LOS (days); and (b) in-hospital mortality. Time trends by calendar year and associations between MOUD and study outcomes were calculated. Results: In 2829 ED patients with acute drug OD, 696 with confirmed opioid OD were included. Overall, 120 patients (17%) were previously prescribed any MOUD, and MOUD prevalence was significantly higher in 2018 and 2019 compared to 2016 (20.1% and 27.8% vs. 8.8%, p < 0.05). Odds of MOUD misuse were significantly higher for methadone (OR 3.96 95% CI 2.57–6.12) and lowest for buprenorphine (OR 1.16, p = NS). Mean LOS was over 50% longer for methadone (3.08 days) compared to buprenorphine and naltrexone (both 2.0 days, p = NS). Following adjustment for confounders, buprenorphine use was associated with significantly shorter LOS (IRR -0.44 (95%CI -0.85, −0.04)). Odds of death were 30% lower for patients on any MOUD (OR 0.70, 95%CI 0.09–5.72), but highest in the methadone group (OR 0.82, 95%CI 0.10–6.74). Conclusions: While MOUD prevalence significantly increased over the study period, MOUD misuse occurred for patients taking methadone, and OD LOS overall was lower in patients with any prior buprenorphine prescription.