National trends in substance use treatment admissions for opioid use disorder among adults experiencing homelessness

Objective: People experiencing homelessness (PEH) have high rates of substance use, and homelessness may be an important driver of health disparities in the opioid overdose epidemic. However, few studies focus on homelessness among the opioid use disorder (OUD) treatment population. We examine national-level trends in substance use treatment admissions among PEH with OUD. Methods: This study used data from first-time treatment admissions in the United States from the Treatment Episode Data Set: Admissions (TEDS-A) to examine characteristics and trends of adults experiencing homelessness who entered state-licensed substance use treatment programs for OUD from 2013 to 2017. We used chi-squared analyses to examine changes in characteristics of this population over time and logistic regression to assess characteristics associated with receipt of medications for opioid use disorder (MOUD) among PEH. Results: Among all adults with OUD entering specialty treatment from 2013 to 2017, 12.5% reported experiencing homelessness. Compared to individuals not experiencing homelessness, PEH were more likely to be male, inject opioids, use cocaine or methamphetamine, and enter into residential detoxification treatment. PEH were less likely to enter outpatient treatment or receive MOUD. From 2013 to 2017, significant increases occurred in the proportion of PEH who had co-occurring psychiatric problems and used methamphetamines. Over time, treatment type shifted significantly from residential detoxification to outpatient treatment. Receipt of MOUD increased among PEH over time (13.7% to 25.2%), but lagged behind increases among individuals not experiencing homelessness. Among PEH, being older was associated with receiving MOUD, while concurrent methamphetamine use [adjusted odds ratio (AOR) 0.63; 95% CI 0.58, 0.69] and living in the southern United States (AOR 0.27; 95% CI 0.25, 0.30) were associated with not receiving MOUD. Discussion: The proportion of PEH with OUD who receive medications as part of treatment increased over time, but three quarters of PEH entering treatment still do not receive this highest standard in evidence-based care. The sharp increase observed in concomitant methamphetamine use in this population is concerning and has implications for treatment.