Buprenorphine/Naloxone dose and pain intensity among individuals initiating treatment for opioid use disorder.

Background: Opioid use disorder and pain often co-occur, complicating the treatment of each condition. Owing to its partial agonist properties, buprenorphine/naloxone (BUP/NX) may confer advantages over full agonist opioids for treatment of both conditions. The optimal dose of BUP/NX for comorbid pain is not known. We examined dose and other factors associated with pain intensity among patients initiating BUP/NX for opioid use disorder.

Methods: We studied 1106 patients initiating BUP/NX treatment for opioid use disorder from 2003 to 2010. Information on pain level, diagnoses, and treatment were extracted from medical records. Eligible patients had at least one self-reported pain intensity numerical rating score (NRS) within 30 days before BUP/NX initiation (baseline) and at least one between 15 and 90 days after BUP/NX initiation (during treatment). The primary outcome was NRS decrease (2 or greater) from baseline to during treatment. We used generalized estimating equations to model odds of the primary outcome with BUP/NX dose as the independent variable of interest in the subset of patients with a baseline NRS ≥ 2.

Results: The sample was 94% male and 73% White. Mean age was 50. Psychiatric and non-opioid substance use comorbidities were common. The following demographic and clinical correlates were associated with a decrease in pain intensity: age 18-29 (compared to 30-39 and 40-49); absence of PTSD diagnosis and absence of a chronic pain diagnosis. BUP/NX dose was not associated with decreased pain intensity in bivariate or multivariable analysis.

Conclusions: BUP/NX maintenance treatment was generally consistent with improvements in pain intensity; however, factors other than BUP/NX dose contribute to improved pain intensity among those initiating the medication.