(54) Determinants of Increased Travel Burden for Patients Treated with Buprenorphine

Background & Introduction: Improving treatment outcomes for persons with opioid use disorder (OUD) requires addressing disparities in access to treatment. Current literature has focused on barriers to accessing prescriber services, overlooking pharmacy access. Even when persons with OUD see a prescriber, adherence depends heavily on the availability and consistency of their medication supply from community pharmacies. This study aims to fill this gap by investigating the spatial and pharmacy-related barriers that persons with OUD face when accessing buprenorphine.

Evidence shows that buprenorphine prescribers are more concentrated in urban and affluent areas, placing significant travel burdens on rural and socioeconomically disadvantaged patients. In a cohort of buprenorphine-treated individuals in Pennsylvania, patients traveled a median distance of 48.4 miles to see a prescriber, and those who traveled farther were 29% less likely to complete a 6-month course of therapy.[1] Similarly, disparities in pharmacy access introduces another challenge. In 2018, only 42.2% of pharmacies in Texas were adequately stocked to fill a 1-week supply of buprenorphine,[2] and only 49% of pharmacies had dispensed the medication,[3] further obstructing treatment.

This study analyzes changes in pharmacy travel distances after initiating buprenorphine for the treatment of opioid use disorder and identifies demographic and geographic corollaries of increased travel distance.

Methods: This retrospective cohort study assesses changes in travel burden for patients accessing buprenorphine for OUD, using three years of data from the Integrated Humana Medical and Pharmacy dataset (2021-2023). The dataset includes patient identifiers, diagnoses, prescriptions, and travel distances data for analysis.

The cohort included patients with a confirmed OUD diagnosis (ICD-9/10 codes 304.XX and F11.XX), at least one buprenorphine prescription (identified by National Drug Code), and continuous insurance enrollment during the study period. Patients who received mail order prescriptions or traveled more than 150 miles to their pharmacy were excluded to reduce outlier effects and ensure the analysis focused on typical community pharmacy access patterns. Change in travel burden was operationalized as the average change in pharmacy travel distances in the 180 days before and the 180 days after buprenorphine initiation.

Travel distance changes were summarized descriptively. Chi-square tests were performed to determine if patients differed on rurality, geographic region of residence, and race were more or less likely to experience an increase in travel distance. Additionally, the study examined the proportion of patients unable to fill buprenorphine at the same pharmacies they used in the 180-days prior to initiating buprenorphine. All analyses were performed using SAS version 9.4.

Results: A total of 5,803 patients were included in the study. Of this total, 38.9% of patients experienced an increase in travel distance after initiating buprenorphine treatment, while 36.7% saw a decrease in travel distance. The remaining 24.4% of patients had no change in their travel burden. For patients who had an increase in travel distance, the mean increase was 8.1 miles (SD:16.0), with a median increase of 1.9 miles. The 90th percentile of increased travel distances was 22.5 miles.

Nearly a quarter (24.5%) of patients with at least one pharmacy claim in the 180 days prior to buprenorphine initiation used entirely different pharmacies to fill their buprenorphine prescriptions. Among these patients who filled buprenorphine prescriptions at a different set of pharmacies, 59.7% experienced an increase in travel distance, while 39.8% saw a decrease. Patients who switched pharmacies and experienced an increase in travel distance had a mean increase of 13.0 miles (SD: 20.3) with a median of 5.1 miles and a 90th percentile increase of 33.5 miles, which suggests substantial variation in travel burden for these patients.

Black patients were significantly more likely to experience an increase in travel distance after initiating buprenorphine compared to white patients (40.7% vs 37.5%, P< 0.001). Geographically, 43.6% of patients in rural areas experienced an increase in travel distance compared to only 36.7% of those residing in urban areas (P < 0.001). Regionally, 41.3% of residents in the Southern United States (US) experienced an increase in travel distances compared to 35.1% of residents in the Northeastern US, 34.3% in the Midwest, and 32.3% in the Western US (P < 0.001).

Conclusion & Discussion: This study highlighted the disparities in travel burden with rural patients and those in the Southern US facing the greatest increase in travel distances. These findings suggest that geographic inequities persist in accessing buprenorphine in community pharmacies, especially in areas with historically limited healthcare resources. The increased travel distance observed in some patients, especially in the 90th percentile, indicates that certain individuals are more vulnerable to pronounced changes in travel distance, which likely impacts treatment adherence and persistence.

Racial disparities were apparent with Black patients disproportionately affected by travel burden changes compared to White and other racial groups. This may reflect existing racial differences in healthcare access, highlighting the need for further research on how social determinants influence OUD treatment. Additionally, the high percentage of patients switching pharmacies post-initiation suggests barriers in pharmacy access, which warrants further investigation into the availability and consistency of buprenorphine services across the regions. Future research should address how area-level demography and local policy impact access to buprenorphine in community pharmacies.

References: 1. Cole ES, DiDomenico E, Cochran G, et al. The Role of Primary Care in Improving Access to Medication-Assisted Treatment for Rural Medicaid Enrollees with Opioid Use Disorder. J Gen Intern Med. Jun 2019;34(6):936-943. doi:10.1007/s11606-019-04943-6
2. Hill LG, Loera LJ, Evoy KE, et al. Availability of buprenorphine/naloxone films and naloxone nasal spray in community pharmacies in Texas, USA. Addiction. Jun 2021;116(6):1505-1511. doi:10.1111/add.15314
3. PMP AWARxE - Appriss Health.