Despite the existence of evidence-based treatment for opioid use disorder (OUD), opioid overdose deaths continue to rise [1]. Only one in five people with OUD in the United States receives any treatment [2], and only 37% of people receiving treatment are prescribed the medications buprenorphine or methadone [3, 4], which improve health outcomes and reduce mortality [5,6,7,8,9]. This treatment gap highlights the need for interventions that address barriers to care and engage out-of-treatment people who use drugs. Barriers that prevent people from receiving appropriate OUD treatment include availability, cost and stigma [10,11,12].
Persons experiencing homelessness (PEH) have higher rates of substance use disorders [13] and substance-related mortality than the general population [14], with opioid overdose as a leading cause of death [15]. Buprenorphine is a recommended treatment for OUD among PEH [16], but these patients face additional barriers to care, including social isolation, discrimination, and competing priorities [16,17,18,19].
Models of care that lower thresholds to treatment with methadone have been developed in Canada and Europe, with success in retaining marginalized patients in care [20, 21], reducing overdose and all-cause mortality [22, 23], and decreasing injection-related risk behaviors among patients who continue to use drugs [24]. While the model is not fully developed and there is some variability in practice, “low threshold” methadone programs prioritize the reduction of drug-related harms over abstinence as the primary treatment goal. Such programs feature flexible attendance and urine drug testing requirements and do not discharge patients with ongoing drug use [25].
Harm reduction syringe access programs are a major provider of services to out-of-treatment people with OUD, and people using these services are often homeless and have faced barriers to accessing buprenorphine treatment despite interest [26,27,28,29,30]. Past interventions to reach these marginalized patients include buprenorphine treatment linkage through harm reduction staff education, motivational interviewing, and referral training [31], and pilot programs that directly provided buprenorphine treatment within harm reduction agencies [32,33,34]. One such pilot program in New York City provided immediate clinical assessment and same-day prescription for buprenorphine, did not require counseling or urine toxicology testing, and accepted patients with goals other than abstinence. Patient retention in the program was 68%, 63%, 56%, and 42% at the end of 3, 6, 9 and 12 months, respectively [32].
Other models of lower threshold treatment for PEH in the United States include buprenorphine treatment provided by a multidisciplinary team at family shelters in Boston, which found that shelter-based treatment was feasible and may have helped patients decrease opioid use, avoid overdose, and maintain employment [35]. Another study found that mobile methadone vans in New Jersey were able to engage a greater proportion of non-white, homeless, uninsured people who inject drugs (PWID) compared to traditional methadone clinics [36].
In 2016, the San Francisco Street Medicine Team started a low barrier buprenorphine treatment pilot program after identifying a need for more accessible treatment among PEH who use heroin. There are an estimated 22,500 people who inject drugs in San Francisco, many of whom are experiencing homelessness, and heroin use and fentanyl deaths are increasing [37].
The Street Medicine Team cares for PEH who are not otherwise able to get their health needs met within San Francisco’s relatively robust safety-net system of care. Patients are engaged by peer outreach workers or self-present on a drop-in basis to either a small open-access medical clinic or a nearby syringe access program, where a clinician provides comprehensive substance use assessment and education and calls in a same-day prescription for buprenorphine/naloxone to be filled at a community pharmacy that dispenses the medication free to patients who are uninsured or have Medicaid. This pharmacy is operated by the Department of Public Health and provides medications for mental health and substance use disorders to the city’s safety net population. In 2018, the Street Medicine Team also began providing treatment at local shelters and homeless encampment health fairs, and some patients who were initially engaged in the clinic or at the syringe access program continued their treatment through these sites. Any patient with OUD experiencing homelessness who is interested in buprenorphine treatment is eligible to participate, including patients with alcohol and benzodiazepine use disorders, pregnant patients, and youth.
Clinicians determine specifics of patient care plans in a flexible manner with attention to prior barriers faced and with support for patients who have ongoing substance use, goals other than abstinence, and treatment interruptions. The team provides an initial prescription for 3–7 days of buprenorphine/naloxone, and patients have weekly visits early in treatment. With written instructions, patients manage their own “home” induction at the location of their choice and are able to titrate to a typical initial dose of 16 mg. Urine toxicology testing is typically performed at least monthly, with testing done more frequently if there are clinical indications. In some cases toxicology testing may be a barrier to care and is deferred, for example if there is no place to collect a sample or if the patient has had prior traumatic experiences with urine testing and would opt to forgo treatment rather than complete the test. Depending on the treatment site, toxicology testing is either point-of-care or send-off testing to the local hospital laboratory.
As they progress in treatment, patients who are stable with abstinence from opioids may have visits as little as monthly. Patients who continue to use heroin but have improvement in functioning and are satisfied with their treatment are not considered unstable and are typically seen every 1–2 weeks. In cases of clinical instability, the team focuses on keeping the patient engaged in care, strongly encouraging higher levels of care when appropriate but also recognizing that realistically many patients will face barriers to engagement in higher levels of care. Patients may be offered the choice of ongoing care through the Street Medicine team with daily observed buprenorphine dosing on weekdays through the community pharmacy or transition to methadone maintenance or residential treatment. Counseling is available and encouraged through partnership with the Center for Harm Reduction Therapy but is not required.
The primary goal of the pilot program is retention in care, with secondary goals of improved health, reduction in opioid use, and abstinence. The Street Medicine team’s target population is highly marginalized and mistrustful of the medical community with a substantial burden of chronic physical and mental illness, and thus the development of trust to facilitate ongoing engagement for medical care, mental health care, harm reduction services, and case management is valuable even in patients who are not continuing to take buprenorphine.
This study aims to describe the results of the pilot program by characterizing the population participating in low barrier buprenorphine treatment, assessing retention in treatment, retention on buprenorphine and reduction in opioid use, and reporting adverse events.