Exploring the Association of State Policies and the Trajectories of Buprenorphine Prescriber Patient Caseloads.

Background: Increasing buprenorphine access is critical to facilitating effective opioid use disorder treatment. Buprenorphine prescriber numbers have increased substantially, but most clinicians who start prescribing buprenorphine stop within a year, and most active prescribers treat very few individuals. Little research has examined state policies' association with the evolution of buprenorphine prescribing clinicians' patient caseloads.

Methods: Our retrospective cohort study design derived from 2006 to 2018 national pharmacy claims identifying buprenorphine prescribers and the number of patients treated monthly. We defined persistent prescribers based on results from a k-clustering approach and were characterized by clinicians who did not quickly stop prescribing and had average monthly caseloads greater than 5 patients for much of the first 6 years after their first dispensed prescription. We examined the association between persistent prescribers (dependent variable) and Medicaid coverage of buprenorphine, prior authorization requirements, and mandated counseling policies (key predictors) that were active within the first 2 years after a prescriber's first observed dispensed buprenorphine prescription. We used multivariable logistic regression analyses and entropy balancing weights to ensure better comparability of prescribers in states that did and did not implement policies.

Results: Medicaid coverage of buprenorphine was associated with a smaller percentage of new prescribers becoming persistent prescribers (OR = 0.72; 95% CI = 0.53, 0.97). There was no evidence that either mandatory counseling or prior authorization was associated with the odds of a clinician being a persistent prescriber with estimated ORs equal to 0.85 (95% CI = 0.63, 1.16) and 1.13 (95% CI = 0.83, 1.55), respectively.

Conclusions: Compared to states without coverage, states with Medicaid coverage for buprenorphine had a smaller percentage of new prescribers become persistent prescribers; there was no evidence that the other state policies were associated with changes in the rate of clinicians becoming persistent prescribers. Because buprenorphine treatment is highly concentrated among a small group of clinicians, it is imperative to increase the pool of clinicians providing care to larger numbers of patients for longer periods. Greater efforts are needed to identify and support factors associated with successful persistent prescribing.