Chronic prescription opioid use predicts stabilization on buprenorphine for the treatment of opioid use disorder

Introduction: Prescription opioid misuse is a risk factor for opioid use disorder (OUD). Patients who misuse prescribed opioids and those who misuse illicit opioids are demographically and medically distinct groups, and research has shown there is heterogeneity in treatment response between these groups. The objective of this study was to measure the adjusted odds of successful stabilization on buprenorphine in patients with baseline prescription opioid use compared to those not prescribed opioids.

Methods: A cohort of patients newly prescribed a buprenorphine product indicated for OUD between January 1 and November 30, 2018, were identified from the Texas Prescription Monitoring Program. We excluded those under the age of 15 and those who filled an opioid prescription after initiating buprenorphine to limit misclassification. We then stratified the cohort based on type of prescription opioid use in the pre-index period. We defined chronic opioid use as being prescribed opioids for a period of 90 out of 120 days, ending no sooner than 90 days prior to treatment initiation. We defined acute opioid use as filling any opioid prescription in the 90 days prior to initiating buprenorphine. The outcome of interest-stabilization on buprenorphine-was met by filling two prescriptions totaling 30-days' supply with no more than a six-day gap in therapy. We used multiple logistic regression to estimate the odds of stabilization in the prescription opioid use categories compared to those with no pre-index, opioid prescriptions.

Results: Among 6756 eligible patients, 44.1% used prescription opioids in the 90 days prior to buprenorphine initiation. Of these, 62.2% met the criteria for acute prescription opioid use and 37.8% for chronic prescription opioid use. Patients with prescription opioid use at baseline were more likely to be older and insured compared to those with no prescription opioid use. After adjustment for covariates, both prescription opioid use groups were significantly more likely to be successfully stabilized on therapy (Acute: aOR = 1.53, 95% CI = 1.37-1.72; Chronic: aOR = 2.43, 95% CI = 2.08-2.85). In a second model, those with chronic prescription opioid use were significantly more likely than those with acute prescription opioid use to be successfully stabilized (aOR = 1.60, 95% CI = 1.31-1.90).

Conclusion: Persistence to buprenorphine treatment for OUD is, in part, dependent on baseline prescription opioid use. This study suggests that patients with chronic prescription opioid use may be more likely than nonprescription opioid users to be successfully stabilized on treatment and may thus benefit more from pharmacotherapy with buprenorphine than those with no prescription opioid use. Failing to account for this variation in future studies of buprenorphine treatment persistence may lead to significant residual confounding and biased results. Extending access to buprenorphine among those with prescription OUD may have a significant impact on opioid related morbidity and mortality.