Association of state medicaid prescription cap policies with trajectories of buprenorphine use for opioid use disorder

Abstract

Background

Buprenorphine and other medications for opioid use disorder (OUD) can reduce opioid-related morbidity and mortality. It is unknown whether state Medicaid prescription cap policies that restrict the monthly number of covered prescription fills affect the duration of buprenorphine use.

Objective

To identify trajectories of buprenorphine use and determine the association of caps with trajectory group membership among individuals with OUD.

Methods

Using 10 states' Medicaid claims data from 2010 to 2015, we employed group-based trajectory models to identify patterns of buprenorphine fills over 12 months. We conducted multinomial logistic regression to estimate the association of cap policies with buprenorphine trajectory group membership, adjusting for individual- and state-level covariates.

Results

Among 69,306 Medicaid enrollees with OUD who initiated buprenorphine, 16.9 % resided in states with caps. The mean age was 36.2 (SD = 9.8) years and 59.2 % were female. We identified five trajectories: consistent use (40.9 %), delayed discontinuation (14.5 %), early discontinuation (26.4 %), gradually declining use (9.5 %), and rebounding use (8.8 %). Caps were associated with greater risk of membership in the early discontinuation group (adjusted relative risk ratio = 1.47, 95%CI = 1.36,1.59, referent = consistent use). Younger age, male sex, Black race, Hispanic ethnicity, non-opioid substance use disorder, history of acute care utilization were also positively associated with early discontinuation.

Conclusions

Medicaid cap policies were associated with increased likelihood of early discontinuation and other trajectories of inconsistent buprenorphine use relative to states without these policies. Medicaid's prominence as a payer for OUD treatment and 12 states' continued implementation of caps warrant safeguards to ensure cap policies do not undermine buprenorphine access.