Mobile methadone medication units: A brief history, scoping review and research opportunity

Abstract

Background.

The Drug Enforcement Administration (DEA) approved the first mobile medication unit (i.e., a van to administer methadone) in 1988 and approved units on an ad hoc basis until issuing a moratorium in 2007 citing concerns about safety and diversion. In February 2020, the DEA released a notice of proposed rulemaking to permit a resumption of mobile medication units. The Biden Administration plans to release the final rule in 2021. Because a preliminary scan suggested limited evidence, a scoping review examined the research related to methadone vans to identify and assess the extent of mobile methadone research and inform the development and implementation of new mobile services.

Methods.

A scoping review, supplemented with key informant interviews, identified and described the most relevant evidence. Ovid MEDLINE and the Cochrane Database of Systematic Reviews databases were searched from inception to July 2020.

Results.

Informant interviews provided perspective on the need for and the use of mobile medication units, the history of methadone vans, and benefits and problems associated with the units. The scoping review found limited evidence: three cohort analyses (one prospective) and one before and after analysis (four studies) of individuals using mobile medication services. Mobile services were associated with enhanced retention in care (relative to patients in fixed site programs) and mobile units appeared to facilitate access for underserved populations with opioid use disorders.

Discussion.

The key informants addressed the history of methadone vans, the potential use to serve rural communities and correctional facilities and the benefits and problems associated with mobile services. The scoping review found evidence that mobile services increase methadone access among underserved populations and may enhance retention in care. The DEA’s proposed regulatory modification creates opportunities to further evaluate the implementation and the effects of mobile medication units.

1.0. Introduction

Mobile methadone medication units (“methadone vans”) emerged in the late 1980s to respond to the spread of HIV infection among people who use drugs and the need to enhance access to opioid treatment programs. The purpose of the vans was to facilitate access to care in rural communities and in urban areas when communities opposed the opening of fixed site opioid treatment programs (OTPs) (Center for Addictive Behaviors, 1994). The Drug Enforcement Administration (DEA) approved the first “clinic on wheels” as a medication unit serving communities in Southeastern Massachusetts in 1988 (Wroblewski, 1988). The mobile service was based on Amsterdam’s “methadone by bus” project that dispensed methadone at stops in high drug use sections of the city (Buning et al., 1990). Subsequently, the DEA authorized additional mobile medication units on an ad-hoc basis (Department of Justice, 2020). In 2007, citing concerns about potential methadone diversion, the DEA issued a moratorium and stopped approving mobile medication units (Vestal, 2018). States, communities and advocates, however, called for the DEA to resume authorizing mobile medication units as one strategy to help address the opioid epidemic (McBournie et al., 2019; Vestal, 2018).

On February 26, 2020, the DEA released a notice of proposed rulemaking to revise Chapter 21 Code of Federal Regulations (CFR) Parts 1300, 1301 and 1304 and amend the “registration requirements for narcotic treatment programs with mobile components” (Department of Justice, 2020). The Controlled Substances Act requires that persons who dispense controlled substances be registered at each “principal place of business” where controlled substances are dispensed. The proposed rule waives that requirement for mobile medication units because vans stop at multiple addresses and eliminated the requirement for mobile services to be registered as a distinct narcotic treatment program separate from the fixed site clinic (i.e., vans operate as medication units for a fixed site clinic) (Department of Justice, 2020). The revisions seek to increase access to OTPs and include provisions to prevent diversion of methadone and buprenorphine (Department of Justice, 2020).

The American Association for the Treatment of Opioid Dependence submitted written comments supporting the proposed DEA changes and the potential to facilitate opioid agonist therapy in rural communities and correctional settings (Parrino, 2020). The Biden-Harris Administration’s Statement of Drug Policy Priorities for Year One included a commitment to “Publish final rules this year regarding … methadone treatment vans” (p. 3) (Office of National Drug Control Policy, 2021).

Although the “methadone vans” were used across the nation, there is uncertainty about the potential impacts and challenges associated with mobile medication units. A preliminary literature scan suggested that few studies examined the operation and impacts of mobile methadone vans. Because the literature was under-developed, we conducted a scoping review of relevant evidence (Munn et al., 2018; Sucharew & Macaluso, 2019). Key informant interviews preceded the scoping review to provide context on the history of mobile medication units including benefits and problems and the potential uses of mobile services. Recognizing that mobile medication units were likely to be approved in the near future, the analysis was designed to inform the development of mobile services and identify important research gaps that could be addressed following the resumption of mobile medication services. The study was conducted as part of a broader assessment of methadone policy research that included a review of drug policy and methadone policy research, nine key informant interviews and summaries of research papers on 11 methadone related topics (McCarty et al., 2020).

2.0. Methods

2.1. Key Informant Interviews.

We completed structured qualitative interviews with nine key informants to provide background and insights into the operations of methadone services prior to conducting the electronic search. A trained qualitative interviewer led the interviews and an associate prepared detailed field notes paraphrasing the interviews. Topics covered in the interview guide included a) the future of OTPs, b) methadone in primary care, c) interim methadone, d) methadone vans, and e) OTPs and COVID-19 changes. Five of the informants commented on either the DEA’s notice of rulemaking for mobile medication units or the initial development of mobile methadone vans.

2.2. Search Strategies.

Ovid MEDLINE and the Cochrane Database of Systematic Reviews databases were searched from inception to July 2020. The initial search generated 3,706 abstracts and, after reviewing the abstracts, 220 papers were selected for review. The abstract review excluded 98 papers and left 122 publications from 109 separate research studies for tabling. Six of the papers addressed mobile medication units or mobile methadone vans. Two were case studies without outcome data and were excluded from the table. A review of reference lists of relevant articles supplemented electronic searches. Details on the search strategy and the literature flow diagram are provided in McCarty et al. (2021).

2.3. Study Selection.

Studies were eligible if they addressed mobile methadone units (e.g., vans or recreational vehicles equipped with a safe to store medication, a central alarm system and a dispensing window), reported outcomes (e.g., treatment initiation, retention in care, drug use) or characteristics of individuals receiving services, and were conducted in the United States. Randomized trials and cohort studies were prioritized for inclusion. One investigator abstracted key information (clinical setting, sample size, intervention/comparison, main findings and key limitations) into a Table; a second investigator verified data. Because this was a scoping review, a descriptive approach summarized the literature and the papers were not formally synthesized or graded (Munn et al., 2018).

3.0. Results

3.1. Key informants.

Key informant interviews provided details on the potential uses of mobile medication units, interest in operating mobile services, how the services would be used, potential problems and challenges with mobile services, and the history of methadone vans. The interviews clarified that there was strong support for the proposed rules and keen interest in operating mobile services. The American Association for the Treatment of Opioid Dependence (AATOD) supported the proposed regulations and anticipated mobile medication units would expand access to methadone in rural communities and correctional facilities (Parrino, 2020). Some OTPs, however, objected to the proposed requirements to return vans to the OTP daily and the inability to operate across state lines (M. Parrino, personal communication, October 02, 2020).

A former Director of SAMHSA’s Division of Pharmacological Therapies, commented that mobile vans have an important, but limited, value in expanding access to methadone treatment access in rural communities (R. Lubran, personal communication, May 1, 2020). Oregon’s State Opioid Treatment Authority (SOTA) was pleased with the proposed rules and noted that SOTAs had drafted a joint letter asking the DEA to authorize mobile services in order to expand access in rural communities (J. McIlveen, personal communication, June 1, 2020).

A former City of Boston health official recalled how he used a methadone van in 1989 to expand the city’s opioid treatment program with stops at two state hospitals in Boston because, “The political and community opposition to siting methadone programs was a problem. The solution was a service that came and went – a mobile service” (V. Capoccia, personal communication, April 20, 2020). Similarly, a methadone investigator explained the development of the Baltimore van, “Joe Brady had an award from National Institutes of Health to test mobile methadone services with a van as a strategy to circumvent zoning restrictions and improve geographic access. The down sides were the operating expense, patients waiting for the van during inclement weather, and vehicle breakdowns” (R. Schwartz, personal communication, May 8, 2020).

3.2. Research Summary.

The research search found no randomized clinical trials and identified four studies using a mobile van. Three studies described the characteristics of individuals receiving mobile methadone services in Baltimore (Greenfield et al., 1996), New Jersey (Hall et al., 2014) and San Francisco (Chen et al., 2009). Two studies compared the characteristics of individuals receiving methadone from fixed site OTPs to those receiving methadone from mobile vans (Greenfield et al., 1996; Hall et al., 2014). In San Francisco, the mobile methadone service agreed to stop in the parking lot of a therapeutic community so that residents could access methadone; the study compared lengths of stay among residents receiving methadone and residents who did not receive methadone (Chen et al., 2009). The final study used the Baltimore methadone van to administer levomethadyl acetate hydrochloride (LAAM) at a syringe exchange (Kuo et al., 2003). The four analyses included a total of 7,780 study participants (Table 1). None of the studies reported problems or challenges associated with mobile methadone services. See Table 1 for a summary of the four studies.

Table 1.

Mobile medication unit research

Author, Year	Design N	Setting	Intervention	Main Findings
Greenfield 1996 (Greenfield et al., 1996)	Retrospective cohort analysis N=1,063	Mobile van vs fixed site OTPs Baltimore	Compared individuals receiving mobile methadone (n=339) vs. OTP admissions from the same zip code (n-664) and OTP admissions living in different zip codes (n=924)	The mobile service had better mean retention (15.5 months) compared to patients from the same zip codes (3.9 months) or different zip codes (6.3 months). Early discharge was associated with higher lifetime arrests, more frequent cocaine use and less family income. Analyses did not control for other patient characteristics.
Hall 2014 (Hall et al., 2014)	Retrospective analysis of individuals enrolled in the NJ-MATI N=6,603, 6 OTPs	6 OTPs and methadone vans in New Jersey. Mobile Medication Units dispensed methadone and buprenorphine at two stops per day six days per week. Patients received counseling at the fixed site OTP.	Compared two groups: 1) patients in six standard OTP (n=2,259); 2) patients with mobile methadone from those same providers (n=2,017)	Individuals receiving methadone from the van were more likely than those treated in an OTP to be men (63% vs. 59%), African-American (43% vs. 24%), older than 35 years (76% vs. 62%), PWID (73% vs. 52%), and uninsured (75% vs. 48%). Multinomial logistic regression suggested NJ-MATI participants were more likely to be older, African American (OR 2.7) or Latino (OR 1.8), with less social capital (OR 0.7), and more likely to be homeless (OR 2.8), and uninsured (OR 3.1) than individuals served in OTPs
Chen 2009 (Chen et al., 2009)	Retrospective cohort analysis N=231	Methadone van San Francisco and a TC. TCs are residential SUD treatment services. Historically, residents have not been allowed to be on methadone. In a novel collaboration, a van stopped daily and dispensed methadone to TC residents.	TC patients receiving methadone (n = 125) vs TC patients not receiving methadone (n = 106)	Both groups had similar retention rates. Illustrates a unique use of mobile services but does not speak to the operation of the service or the patients served.
Kuo 2003 (Kuo et al., 2003)	Prospective cohort of syringe exchange customers referred to a mobile LAAM program N = 114	Service based on Baltimore’s methadone van; the van stopped at a syringe exchange to provide LAAM three days per week. The study tested a low-threshold drug treatment strategy.	Individuals using a syringe exchange (n=163) were referred to the service. 114 (70%) received LAAM. 96 (84% of those who initiated LAAM) completed a baseline and 30- day ASI and 82 (72% of those who initiated LAAM) completed a 90- day follow-up interview.	At the 30-day ASI, there were significant reductions in ASI Drug, Alcohol and Legal composite scores. At the 90-day interview, positive urine screens declined from 86% to 59% for heroin and from 89% to 69% for cocaine. Study documented feasibility of recruiting and retaining individuals from syringe exchange services. At baseline, Nearly two-thirds had no prior OTP treatment.

Abbreviations: LAAM = levomethadyl acetate hydrochloride; NIDA = National Institute on Drug Abuse; NJ-MATI = New Jersey Medication Assisted Treatment Initiative; NR = not reported; OR = odds ratio; OTP = opioid treatment program; PWID = people who inject drugs; TC = therapeutic community;

Baltimore methadone van.

The retrospective Baltimore analysis assessed patient retention in care among individuals receiving methadone from a van (n=349) compared with individuals served in six fixed site OTPs from the same zip codes (n = 665) where the individuals served by the van lived or from other zip codes (n = 924) using 37 months of admission data (Greenfield et al., 1996). Patients receiving methadone from the van were less likely to be referred from social services (13% vs 29%) and were more likely to be Black (89% vs 69%), men (67% vs 51%) with daily cocaine use (35% vs 28%). Retention in care was strongest among individuals receiving methadone from the mobile van (mean 15.5 months) compared to patients served in OTPs from same zip codes (mean 3.9 months) and from other zip codes (mean 6.3 months) (p<0.001). After controlling for prior arrests, daily cocaine use, and family income, individuals using the van were less likely to have early discharges than individuals from the same or other zip codes (Greenfield et al., 1996).

New Jersey Medication Assisted Treatment Initiative (NJ-MATI).

Using administrative data, the study team compared the characteristics of individuals enrolled in mobile medication units versus fixed site opioid treatment programs. The mobile van patients were more likely to be Black (OR [odds ratio] 2.7; 95% CI [confidence interval] 3.3 to 4.7), Latino (OR 1.8; 95% CI 1.5 to 2.1), uninsured (OR 3.1; 95% CI 2.7 to 3.5), injection drug users (OR 2.9; 95% CI 2.6 to 3.4), or homeless (OR 2.8; 95% CI 2.3 to 3.6), and less likely to be married (OR 0.7; 95% CI 0.5 to 0.8) (Hall et al., 2014). Retention in care was not reported.

San Francisco Van.

A third cohort study used San Francisco’s methadone van to provide methadone for individuals living in a therapeutic community (Chen et al., 2009). The secondary analysis was based on data from a five-year study comparing treatment outcomes for residents (n = 125) enrolled in a methadone program prior to TC admission and residents (n =106) who were not enrolled in an OTP prior to admission. Therapeutic communities traditionally operated on a “drug-free” philosophy and did not accept patients on methadone (Sorensen et al., 2009). San Francisco’s methadone van stopped in the therapeutic community’s parking lot to administer methadone medication for therapeutic community residents (and reduced the burden of daily travel to an OTP). The groups with and without methadone had similar mean lengths of stay in the therapeutic community (methadone = 167 days; no methadone = 180 days) and equivalency testing documented similar survival curves. There were no significant differences between those who participated in mobile methadone services compared to residents who did not receive methadone in socio-demographic, substance use, or health characteristics; the baseline Addiction Severity Index (ASI) Drug Composite Score, however, was elevated among residents admitted on methadone (Chen et al., 2009).

Opioid agonist therapy at a syringe exchange.

A before-and-after assessment prospectively recruited study participants from a syringe exchange program in Baltimore and offered them opioid agonist therapy with levomethadyl acetate hydrochloride (LAAM) (a long-acting opioid agonist medication) (Kuo et al., 2003). The Baltimore methadone van provided LAAM medication three times per week at the syringe exchange. The syringe exchange referred 163 potential participants to the service, 114 (70%) enrolled in the study and initiated LAAM, 96 (84% of those who initiated LAAM) completed at least 30 days and 82 (72% of those who initiated LAAM) completed three-months in care. An ASI interview and urine screen were completed at the one-month and three-month interviews. After 30 days of care, ASI composite scores improved significantly for the Alcohol, Drug and Legal scales and urine screens suggested continued use of heroin (86% positive) and cocaine (89% positive). After 90 days of care, positive urine screens declined to 59% for heroin and 69% for cocaine (Kuo et al., 2003). Outcomes improved even though the study participants continued to obtain sterile syringes from the syringe exchange.

4.0. Discussion

The scoping review found sparse evidence on mobile methadone vans. The evidence suggests that mobile units provided access to individuals with opioid use disorders who might otherwise lack access due to patient characteristics (e.g., race/ethnicity, insurance status, and housing instability) (Hall et al., 2014). Evidence on effects on patient outcomes, however, was limited. One study reported a mobile service was associated with enhanced retention in care compared to patients in a fixed site opioid treatment program (Greenfield et al., 1996). The LAAM analysis reported reductions in opioid and cocaine use following enrollment in mobile services among individuals using a syringe exchange service (Kuo et al., 2003). The San Francisco study did not compare retention in care with individuals enrolled in a fixed site OTP and the methadone and comparison groups were not randomized. In sum, the body of research on mobile medication units is limited and weak.

None of the studies reported any data on problems related to mobile methadone services. Key informants, however, remembered that mechanical difficulties sometimes disrupted van schedules and that patients were inconvenienced in snowy and rainy weather. The costs of operating the van, moreover, were substantial. They also commented on security risks for staff and risks of potential diversion. AATOD asked SOTAs for information on theft from methadone vans operating in their states prior to the moratorium on van approvals and the 18 responding SOTAs reported no incidents of theft (M. Parrino, personal communication, October 2, 2020). Potential problems and threats, however, need more systematic evaluation.

The DEA’s proposed revision to Chapter 21 CFR Parts 1300, 1301 and 1304 creates opportunities for mixed methods implementation and effectiveness research on the initiation, operation and evaluation of mobile medication services. Key aspects of the proposed regulations include requirements that a) mobile medication units operate under the OTP’s DEA registration, the mobile service must remain within the state, return to the OTP site each day, must have four or more wheels and cannot be a trailer (Part 1300 of 21 CFR), b) the local DEA office must approve the application and the unit must include security systems to protect controlled medications (Part 1301) and c) all records must be housed at the OTP and electronic records are permitted (Part 1304) (Department of Justice, 2020).

4.1. Limitations

The major limitation of the scoping review is the lack of evidence. There were no randomized trials and the observation studies had limitations including the failure to report patient outcomes (Hall et al., 2014), no comparison group (Kuo et al., 2003), a less relevant comparison group (Chen et al., 2009) and failure to control for confounders (Kuo et al., 2003). The LAAM study was a pre-post feasibility analysis without a comparison group so it is difficult to attribute the outcomes to access to the van and the findings may not generalize to other opioid agonist therapies.

4.2. Research Opportunities

When the final rule on mobile medication units is released, OTPs anticipate operating and expanding mobile services with a focus on rural communities and correctional facilities. They will be implementing services without data on the effectiveness of the services to enroll and retain patients in care. The scoping review suggests that a) the current evidence is too limited to support a full systematic review and b) there is a lot unknown and suggests key research priorities.

Research is required to understand the benefits, problems and patient outcomes associated with mobile medication services. Investigators can collaborate with SOTAs and OTPs that operate mobile services. It will be challenging to conduct randomized trials; cohort studies using electronic health records could provide useful information on patient characteristics, retention in care, and reductions in opioid use. The strongest studies would be prospective cohorts that include relevant comparison groups (e.g., fixed-site methadone), and adjust for covariates. Implementation studies could assess organizational and staffing variables associated with successful mobile units. Mixed methods analyses include quantitative assessments of outcomes following implementation (e.g., retention, continued opioid use, other drug and alcohol use, quality of life) with complementary qualitative analyses to identify barriers, facilitators and problems (e.g., mechanical breakdowns, waiting in inclement weather, diversion) associated with the operation of mobile methadone services. Economic analyses are necessary to assess the cost of mobile services and the economic benefits of the services.

The initial opportunity to assess the operation and impact of mobile medication units was missed; this is a moment to prepare to study the expansion and use of vans in future research. Research is needed to clarify the benefits of mobile medication units and to assess potential problems. This time, we should seize the opportunity for valid and useful assessments of the effectiveness and operations of mobile services to administer and dispense medications for opioid use disorder.

Highlights.

• The Drug Enforcement Administration (DEA) ceased approving methadone vans in 2007

• DEA issued a proposed rule in February 2020 to renew approvals of methadone vans

• A scoping review was completed to assess research on methadone vans

• The search identified 3 cohort studies and a before-and-after analysis.

• The renewal of DEA approvals offers opportunity for research on methadone vans