Peer Recovery Support in the Homeless Health Care Setting (SUPPORT)

### Study Rationale

Developing effective strategies to improve opioid use disorder (OUD) treatment retention among people experiencing homelessness (PEH) is important to reducing mortality in this high-risk population. Evidence from general OUD treatment settings suggests that peer recovery support services may improve treatment engagement and outcomes. Peer recovery support may be particularly beneficial for PEH, who often experience adverse social determinants of health, have limited social support, and face challenges navigating health care and social service systems.

The investigators developed a peer recovery support intervention tailored to the homeless health care setting, informed by patient focus groups, interviews with key informants from Health Care for the Homeless programs, and a community-engaged modified Delphi process.

### Study Objectives

The objective of this randomized pilot trial is to evaluate a 90-day peer recovery support intervention designed to improve OUD treatment retention among PEH. The primary objectives are to assess the feasibility of study procedures, intervention feasibility and acceptability, and intervention fidelity. Secondary objectives include exploring preliminary differences in OUD treatment retention and other clinical and psychosocial outcomes between study arms. Findings will inform intervention refinement and the design of a future, larger randomized controlled trial.

### Study Design and Setting

This study is a two-arm randomized pilot trial involving 40 adults with OUD initiating a new treatment episode at the Boston Health Care for the Homeless Program (BHCHP) office-based addiction treatment (OBAT) program at Jean Yawkey Place in Boston, Massachusetts.

Potential participants will be identified through collaboration with OBAT clinicians and staff and through electronic health record reports identifying patients initiating a new OBAT treatment episode. Interested individuals will undergo eligibility screening and informed consent within 7 days of their initial OBAT visit.

Following informed consent, participants will be randomized in a 1:1 ratio to receive either usual OBAT care (n=20) or peer recovery support in addition to usual OBAT care (n=20). Randomization will be conducted using REDCap. Study assignment will be concealed from participants until completion of the baseline survey.

### Study Procedures

Participants in both study arms will complete a baseline survey and a 90-day follow-up survey. Surveys will assess substance use, mental health, social support, and other factors potentially associated with OUD treatment engagement.

Following completion of the baseline survey, participants will be informed of their study assignment. Participants randomized to the intervention arm will be introduced to the peer recovery support specialist through a warm handoff whenever feasible. When an in-person introduction is not possible, the peer recovery support specialist will initiate outreach following enrollment.

Participants randomized to the usual care arm will continue to receive standard OBAT care without the addition of study-provided peer recovery support services.

### Peer Recovery Support Intervention

Participants randomized to the intervention arm will be offered 90 days of individualized support from a peer recovery support specialist in addition to usual OBAT care. The intervention is grounded in principles of harm reduction and patient-centered care, with an emphasis on developing trusting relationships and addressing barriers to OUD treatment engagement.

During the intervention period, the peer recovery support specialist will aim to meet with participants approximately weekly. The frequency, timing, duration, and content of sessions will be tailored to participants' needs, preferences, and availability. Additional contacts or meetings may occur as needed. Sessions may take place in person, by telephone, or by videoconference, with in-person meetings encouraged when feasible. Text messaging may also be used for communication and coordination with participants who provide consent.

Intervention activities may include emotional and recovery support, assistance navigating health care and social service systems, development of recovery-related skills and goals, and connections to treatment and community resources. The specific support provided will be individualized based on each participant's needs and goals.

Participants without access to a mobile phone will be provided with a phone and prepaid service to facilitate communication with the peer recovery support specialist.

Throughout the intervention period, the peer recovery support specialist will meet approximately weekly with an experienced supervisor to review intervention delivery, participant engagement, peer support boundaries, and challenging situations. Additional supervision will be available as needed.

The peer recovery support specialist will document all participant contacts and outreach attempts using standardized forms in REDCap. Documentation will include the frequency, duration, and mode of contact, as well as intervention components delivered. These data will be used to assess intervention delivery and fidelity.

At the conclusion of the 90-day intervention period, the peer recovery support specialist will work with participants, as appropriate, to identify ongoing sources of peer, clinical, or community support.

### Follow-up and Data Collection

Participants in both study arms will be invited to complete a follow-up survey between 90 and 105 days after randomization. Follow-up assessments may be completed in person or by telephone.

Participants randomized to the intervention arm will also be invited to complete a qualitative exit interview lasting approximately 45-60 minutes. Interviews will explore participants' experiences with the intervention, including its acceptability, perceived benefits, fit with participants' needs, and implementation. Interviews will be audio-recorded for qualitative analysis.

Electronic health record data will also be collected to assess OUD treatment engagement and retention during the study period. These data, together with participant surveys, intervention documentation, and qualitative interviews, will be used to evaluate the pilot trial objectives.