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.