Association Between Cost-Sharing and Buprenorphine Prescription Abandonment

Background: Prior studies suggest cost-sharing decreases buprenorphine dispensing. However, these studies used databases that only report prescriptions filled by patients, not those that were "abandoned." Consequently, the studies could not calculate the probability of buprenorphine prescription abandonment or evaluate whether cost-sharing is associated with abandonment.

Objective: To evaluate the association between cost-sharing and buprenorphine prescription abandonment.

Design: Cross-sectional analysis of the IQVIA Formulary Impact Analyzer, a pharmacy transaction database representing 63% of U.S. retail pharmacies. The database includes transaction records ("claims") for prescriptions even if they are not filled.

Participants: Buprenorphine claims in 2022 among commercially insured and Medicare patients.

Main measures: We evaluated the association between cost-sharing per 30-day supply and abandonment using logistic regression, controlling for patient characteristics, product type, and buprenorphine use in the prior 180 days. We assessed for effect modification by prior buprenorphine use.

Key results: Analyses included 2,346,994 and 1,242,596 buprenorphine prescription claims for commercially insured and Medicare patients, respectively. Among these claims, mean (SD) cost-sharing per 30-day supply was $28.1 (46.4) and $8.4 (20.2), and 1.5% and 1.2% were abandoned. Each $10 increase in cost-sharing per 30-day supply was associated with a 0.09 (95% CI: 0.09, 0.10) and 0.09 (95% CI: 0.08, 0.10) percentage-point increase in abandonment among commercially insured and Medicare patients. Among commercially insured and Medicare patients without prior buprenorphine use, respectively, a $10 increase in cost-sharing per 30-day supply was associated with a 0.12 (95% CI: 0.11, 0.14) and 0.13 (95% CI: 0.07, 0.18) percentage-point higher increase in the probability of abandonment compared with patients with > 90 days of prior buprenorphine use.

Conclusions: Among commercially insured and Medicare patients, buprenorphine prescription abandonment is rare and only minimally associated with cost-sharing. Findings suggest elimination of buprenorphine cost-sharing should only be one component of a larger, multi-faceted campaign to increase buprenorphine dispensing.