Assessing the feasibility, acceptability and accessibility of a peer-delivered intervention to reduce harm and improve the well-being of people who experience homelessness with problem substance use: the SHARPS study.

Background: For people experiencing homelessness and problem substance use, access to appropriate services can be challenging. There is evidence that the development of trusting relationships with non-judgemental staff can facilitate service engagement. Peer-delivered approaches show particular promise, but the evidence base is still developing.

Methods: The study used mixed methods to assess the feasibility, acceptability and accessibility of a peer-delivered, relational intervention to reduce harms and improve health/well-being, quality of life and social functioning, for people experiencing homelessness and problem substance use. Four Peer Navigators were employed to support individuals (n = 68 total, intervention participants). They were based in outreach services and hostels in Scotland and England. Qualitative interviews were conducted with intervention participants, Peer Navigators and staff in services, and observations were conducted in all settings. Quantitative outcomes relating to participants' substance use, physical and mental health, and quality of the Peer Navigator relationship, were measured via a 'holistic health check' with six questionnaires completed at two time-points.

Results: The intervention was found to be acceptable to, and feasible and accessible for, participants, Peer Navigators, and service staff. Participants reported improvements to service engagement, and feeling more equipped to access services independently. The lived experience of the Peer Navigators was highlighted as particularly helpful, enabling trusting, authentic, and meaningful relationships to be developed. Some challenges were experienced in relation to the 'fit' of the intervention within some settings. Among participants there were reductions in drug use and risky injecting practices. There were increases in the number of participants receiving opioid substitution therapy. Overall, the intervention was positively received, with collective recognition that the intervention was unique and highly valuable. While most of the measures chosen for the holistic health check were found to be suitable for this population, they should be streamlined to avoid duplication and participant burden.

Conclusions: The study established that a peer-delivered, relational harm reduction intervention is acceptable to, and feasible and accessible for, people experiencing homelessness and problem substance use. While the study was not outcomes-focused, participants did experience a range of positive outcomes. A full randomised controlled trial is now required to assess intervention effectiveness.

Trial Registration: Study registered with ISRCTN: 15900054.