Higher buprenorphine dose associated with increased treatment retention at low threshold buprenorphine clinic: A retrospective cohort study

Introduction: Controversy exists regarding effective sublingual buprenorphine dosing for treatment of opioid use disorder (OUD), leading to dose caps of 16 mg per day. The Project Connections at Re-Entry (PCARE) program is a low-threshold buprenorphine clinic that provides medication for OUD to vulnerable populations in Baltimore City.

Objectives: To compare retention in care based on treatment dose of buprenorphine, and to examine associated population characteristics.

Methods: This analysis includes clinical patients who received buprenorphine treatment at PCARE between January and July 2021. The study categorized patients into two dosing groups (16 mg or >16 mg). We conducted chi-square tests of independence for categorical variables and independent sample t-tests for continuous variables to evaluate any significant differences in demographic and clinical characteristics by dosing category. To examine differences in 30- and 90-day retention, we conducted multivariable logistic regression analyses with the outcome variable defined as successful retention (at 30 and 90 days, respectively) controlling for demographic and clinical characteristics.

Results: In the study period, 566 patients received buprenorphine treatment at the PCARE van. Patients were primarily male (70.9 %), Black (89.4 %), had a mean age of 46.3 years (SD = 11.5), and a mean opioid use of 22.1 years (SD = 13.5). The majority had previous criminal justice involvement (73.9 %), Medicaid insurance coverage (75.4 %), and were unemployed (69.6 %). Nearly half of the sample had reported a previous overdose event (48.4 %). The study found no significant demographic differences between patients receiving 16 mg of buprenorphine per day compared to patients receiving >16 mg. Patients receiving >16 mg had significantly higher rates of treatment retention at 30 and 90 days: 95.4 % vs 86.7 % (p = 0.001), and 82.7 % vs. 67.6 % (p < 0.001) than those receiving 16 mg, respectively. In a multivariable logistic regression controlling for demographic and drug use characteristics, odds of 30-day (Adjusted Odds Ratio [AOR] = 3.98, 95 % Confidence Interval [CI] = 1.92, 8.74, p < 0.001) and 90-day retention (AOR = 2.56, 95 % CI = 1.55, 4.22, p < 0.001) were greater among patients receiving >16 mg daily compared to 16 mg.

Conclusions: In this study examining patients with OUD in a low-threshold buprenorphine clinic, we observed higher rates of treatment retention with buprenorphine doses >16 mg.