Lead/Presenter: Corey Hayes, COIN - North Little Rock
All Authors: Hayes CJ (Center for Mental Healthcare and Outcomes Research, Central Arkansas Veterans Healthcare System; Department of Biomedical Informatics, UAMS), Raciborski R (Center for Mental Healthcare and Outcomes Research, Central Arkansas Veterans Healthcare System) Martin BC (Division of Pharmaceutical Evaluation and Policy, College of Pharmacy, University of Arkansas for Medical Sciences) Gordon AJ (Informatics, Decision-Enhancement, and Analytic Sciences (IDEAS) Center, VA Salt Lake City Health Care System; Division of Epidemiology, Department of Internal Medicine, University of Utah School of Medicine) Cucciare MA (Center for Mental Healthcare and Outcomes Research, Central Arkansas Veterans Healthcare System; Center for Health Services Research, Department of Psychiatry, College of Medicine, University of Arkansas for Medical Sciences; Veterans Affairs South Central Mental Illness Research, Education and Clinical Center)
Objectives:
Medication for opioid use disorder (MOUD) is the standard of care for treatment of OUD, prevents overdoses, and reduces drug-related morbidity. However, retention on MOUD is essential to attaining these important patient outcomes. The Veterans Health Administration is improving access to MOUD, particularly for buprenorphine since it can be easily attained from pharmacies, in hopes of improving MOUD retention. Therefore, the purpose of this study is to evaluate the changes in buprenorphine retention rates from 2006-2020 and determine if observed changes in buprenorphine retention differed by race and rurality, two Veteran characteristics for which access to care has varied among recipients of buprenorphine.
Methods:
This retrospective cohort study was conducted among U.S. Veterans who were diagnosed with OUD and initiated treatment with buprenorphine between fiscal years 2006-2020. We identified the date in which the Veteran initiated buprenorphine and followed the Veteran until the Veteran either discontinued buprenorphine, reached 180 days of continuous buprenorphine therapy, met the end of the study timeframe (i.e., end of fiscal year 2020), or died. We used Kaplan-Meier curves to describe the days until buprenorphine discontinuation and unadjusted and adjusted accelerated failure time models to estimate the association between year of buprenorphine initiation and days on buprenorphine treatment [using acceleration factors (AF)]. In addition to buprenorphine initiation year, other model covariates included rurality, race, ethnicity, gender, age, social vulnerability index measures, employment status, homelessness, justice involvement, dose and days’ supply of initial buprenorphine prescription, priority status, census division, Elixhauser index score, and location of buprenorphine initiation. We also included interaction terms between year of buprenorphine initiation and race and rurality to test whether differences in retention over time also differed by these two Veteran characteristics.
Results:
Of 46,366 Veterans included, most were White (78.9%), from urban areas (84.3%), male (92.5%), unemployed (65.5%), and initiated buprenorphine in an outpatient setting (74.1%). On average, time to buprenorphine discontinuation within the 180-day period after buprenorphine initiation was 108.8 days (SD = 74.1) over all years and 91.5 days (SD = 75.9) in 2006 compared to 112.5 days (SD = 74.1) in 2019 (last year without censoring). The unadjusted accelerated failure time model indicated that time to discontinuation of buprenorphine was increasing with each year (AF = 0.98, 95%CI: 0.97, 0.98, p < 0.0001). The adjusted model found similar results (AF = 0.97, 95%CI: 0.97, 0.98, p < 0.0001). Interaction terms for rurality were not significant. However, Black Veterans are seeing slower rates of improvements in buprenorphine retention as compared to White Veterans (AF = 0.99, 95%CI: 0.97, 0.99, p = 0.0335).
Implications:
Retention rates on buprenorphine for the treatment of OUD improved modestly over the past 15 years. Gains in buprenorphine retention did not differ by rurality status, but rates of improvement in buprenorphine retention have been slower for Black Veterans compared to White Veterans.
Impacts:
Additional efforts are needed to continue to improve retention rates on buprenorphine as improvements have been minimal over time. In addition to efforts to improve buprenorphine retention overall, specific, targeted efforts are needed for Black Veterans since their improvements over time are lagging behind those of White Veterans.