(26) Overcoming Barriers to Outpatient Buprenorphine Treatment for Opioid Use Disorder

Background & Introduction: Opioid use disorder (OUD) is a chronic medical condition that disproportionately affects Black and Native communities who bear the highest burden of opioid overdose mortality in the US[1]. Recent studies show an increase in OUD among minoritized groups who historically face limited healthcare resources[1]. Camden County, New Jersey, is a diverse community which has struggled with longstanding disparities in healthcare access and resources.
To improve access to buprenorphine treatment for OUD, there has been a call for a “low-threshold” approach, with a medication first model to ensure patients can access buprenorphine scripts[2]. Patients have identified flexibility of services and a harm reduction approach as positive features of low threshold walk-in visits in urban areas[3]. Applying this approach, a clinic in Toronto, Ontario saw 42% of patients retained following treatment initiation through a walk-in and 65% of OUD patients continued buprenorphine treatment after initiation[4]. In other health care settings walk-in access has been shown to benefit racially and socially underserved groups[5], but there is scant evidence of whether these trends hold for patients in OUD treatment. This study assesses the effectiveness of low-threshold walk-in visits at increasing access for populations less likely to engage with healthcare.

Methods: This is a retrospective cohort study of 1895 patients (Mage = 40.5, SDage = 11.9, 736 female) aged 18 years or older who received buprenorphine treatment from an outpatient clinic. Data was collected by medical record abstraction of electronic medical records (EMR) from the three months before and after opening a low-barrier walk-in clinic.
We used chi-squared tests of independence and post-hoc pairwise comparisons with Bonferroni correction to capture categorical differences between the Before walk-in and After walk-in groups along demographic (age, sex, race/ethnicity, preferred language, housing status) and treatment-related (previous buprenorphine treatment 30 days prior to first visit, location of treatment, and treatment provider) variables.
We further examined the demographics of patients who were more likely to have a walk-in encounter compared to a scheduled appointment. This logistic regression model included encounter type (walk-in or scheduled) as the outcome variable with sex, race/ethnicity, and housing status as predictors. Model results are reported as odds ratio likelihood of having a walk-in over a scheduled encounter.

Results: The clinic saw an increase in patient access to outpatient treatment with the availability of a low barrier walk-in clinic, notably a 29.01% increase in attendance for Black/African American patients (χ2 (1) = 39.2, padj < .001), a 29.8% increase for Hispanic/Latino patients (χ2 (1) = 22.4, padj < .001), and a 29.82% increase in patients with unstable housing (χ2 (1, N = 456) = 38.2, padj < .001). We saw an increase in attendance for patients previously treated at an acute rehab center (48.1%, χ2 (1, N = 77) = 17.78, padj < .001) and during incarceration (75.82%, χ2 (1, N = 91) = 52.32, padj < .001), and patients who purchased non-prescribed buprenorphine (52.27%, χ2 (1, N = 88) = 24.05, padj < .001). In the logistic regression model, we found that Black/African American patients were 38% more likely to seek care at the walk-in clinic rather than scheduling an appointment compared to White patients (β = .32, OR = 1.38, CI = [1.03, 1.85], p = .03). Male patients were 38% more likely than female patients to walk in than to have a scheduled appointment (β = .32, OR = 1.38, CI = [1.05, 1.82], p = .02).

Conclusion & Discussion: Opening the walk-in clinic was associated with a substantial increase in overall clinic utilization, with the largest relative gains among groups that often face barriers to care, including men, Black/African American and Hispanic/Latinx patients, and patients with unstable housing. In addition, attendance also increased among patients with no prior buprenorphine treatment and among those whose prior treatment occurred outside the Cooper health system or in nontraditional settings (during incarceration or via self-treatment), suggesting the clinic lowered thresholds for both entry and re-entry into OUD care. Lastly, looking at the After walk-in cohort, Black/African American and male patients preferred presenting as walk-ins than scheduling in advance. Given that Camden County has high rates of OUD, opioid overdose mortality, and people experiencing homelessness, access to buprenorphine in this area is crucial. Health needs related to OUD and co-occurring conditions may further hinder appointment adherence, contributing to downstream challenges in retention. These patterns indicate that maintaining parallel pathways, both walk-in and scheduled encounters, can serve heterogeneous preferences and circumstances.
The urban, single site study sample limits generalizability despite serving a diverse region. Additionally, the study did not account for transportation access or co-occurring substance use, factors to be considered in the future.

References: 1. Sledge, D., & Hoang, B. L. (2024). Racial/ethnic representation in opioid use disorder-related clinical trials. Journal of substance use and addiction treatment, 161, 209338. https://doi.org/10.1016/j.josat.2024.209338
2. Jakubowski, A., & Fox, A. (2020). Defining Low-threshold Buprenorphine Treatment. Journal of addiction medicine, 14(2), 95–98. https://doi.org/10.1097/ADM.0000000000000555
3. Snow, R. L., Simon, R. E., Jack, H. E., Oller, D., Kehoe, L., & Wakeman, S. E. (2019). Patient experiences with a transitional, low-threshold clinic for the treatment of substance use disorder: A qualitative study of a bridge clinic. Journal of substance abuse treatment, 107, 1-7.
4. Wiercigroch, D., Sheikh, H., & Hulme, J. (2020). A rapid access to addiction medicine clinic facilitates treatment of substance use disorder and reduces substance use. Substance Abuse Treatment, Prevention, and Policy, 15(1), 4.
5. Kroll, D. S., Latham, C., Mahal, J., Siciliano, M., Shea, L. S., Irwin, L., ... & Gitlin, D. F. (2019). A successful walk-in psychiatric model for integrated care. The Journal of the American Board of Family Medicine, 32(4), 481-489.