Factors associated with emergency room visits among patients with opioid use disorder: A study of buprenorphine-treated and untreated patients.

Objective: Identify factors associated with 6-month emergency room (ER) outcomes in patients with opioid use disorder (OUD) and/or treated with buprenorphine (extended-release [BUP-XR] or transmucosal [BUP-TM]). Compare baseline characteristics and 6-month ER visits and healthcare resource utilization (HCRU) across treatment groups. Methods: Patient claims data from September 2017- March 2022 were analyzed for patients diagnosed with OUD and/or treated with buprenorphine. Adjusted logistic regression models were used to identify factors associated with ER visits 6-months post-index. Results: 543 patients initiating BUP-XR, 52,569 BUP-TM and 57,125 patients with OUD diagnosis but no-medications for opioid use disorder (MOUD) were identified.Patients who received BUP-XR (OR: 0.43, 95 % CI: 0.36-0.53) or BUP-TM (OR: 0.78; CI: 0.76-0.81) had lower odds for an all-cause post-index ER visit compared to those with no MOUD treatment.Patients with later index years or those who had an opioid overdose ER visit in the baseline period had higher odds of post-index all-cause and opioid overdose ER visits.1.2 % in BUP-TM cohort and 1 % in the no MOUD cohort had an opioid overdose ER visit, compared to 0 % in the BUP-XR cohort. The BUP-XR cohort had lower rates of inpatient stays, ER visits, and outpatient physician office visits compared to the BUP-TM and no MOUD cohorts but incurred higher pharmacy costs. Conclusions: This study found that any buprenorphine treatment, particularly BUP-XR, was associated with lower odds of all-cause ER visits compared to patients with no MOUD, and highlighted potential risk factors that could help reduce the demand on ER services.