Secondary Analysis of Pain Outcomes in a Large Pragmatic Randomized Trial of Buprenorphine/Naloxone Versus Methadone for Opioid Use Disorder.

Objective: Opioid use disorder (OUD) is associated with chronic pain. We investigated the association between medication treatments for OUD and pain in a post-hoc secondary analysis of a randomized trial of methadone versus buprenorphine/naloxone.

Methods: 1241 individuals with OUD participated in an open label, pragmatic randomized trial of methadone versus buprenorphine/naloxone in nine treatment programs licensed to dispense agonist medication for OUD between 2006 to 2009. In this post-hoc analysis, pain was dichotomized (present or not present) using responses from the Short Form-36. Logistic regression models were fit to test the effect of (1) having baseline pain on week 24 retention, (2) treatment assignment on improvement in pain among those reporting pain at baseline, and (3) pain improvement at week 4 on week 24 retention among those reporting pain at baseline.

Results: Almost half (48.2%) of the sample reported pain at baseline. Participants with baseline pain did not significantly differ in week 24 retention compared to those without baseline pain. Among those reporting pain at baseline, there was no significant difference between treatment arms in improvement of pain at week 4, but improvement in pain at week 4 was associated with significantly greater odds of being retained at week 24 (OR [95% CI] = 1.76 [1.10, 2.82], P = 0.020).

Conclusion And Relevance: In this large multisite randomized trial of medication treatments for OUD, nearly half of the participants reported pain at baseline, and improvement in pain early in treatment was associated with increased likelihood of retention in treatment.