OPSPrep: Developing the service and evaluation model for overdose prevention services NIHR Programme Development Grant Final Report

Background: The UK is experiencing an on-going crisis of drug-related deaths. Overdose prevention centres (OPCs) are spaces where people use illicit drugs in the presence of staff who can intervene in any overdoses that
occur. Implemented in 17 countries since the 1980s, no officially sanctioned OPC has yet operated in the UK.
Original objective(s): To produce research tools and develop the service model to support the evaluation of UK site(s) in a programme grant for applied research (PGfAR).
Methods: We carried out a realist review of international evidence on OPCs pre-registered in PROSPERO (CRD42023414273); created a core outcome set (COS) for OPCs pre-registered using COS-STAP Items and at COMET Initiative (OSF.IO/KW8JM); created an epidemiological and economic model of an OPC in England; and created a service implementation model for OPCs. We involved PPI partners facilitated by a specialist consultant with lived experience of injecting drug use, who brought networks of experts-by-experience. The epidemiological model simulated a generic England setting (England wide data) for scenarios with different OPC coverage and
frequency of OPC use, with estimates of effect from other countries’ OPC data. Economic costs/benefits for the NHS of establishing the OPC over 20 years including potential savings from five outcomes were estimated.
Key findings: Our realist review described a main causal path through which OPCs can produce positive outcomes by triggering mechanisms of feeling safe, trust and social inclusion. Our wider programme theory identified contexts and mechanisms, specific to variations in gender and racial identity, and local drug markets. To develop the Core Outcome Set, 326 individuals ranked 106 outcomes, prioritising 43 outcomes. These were discussed at two
consensus meetings which reduced these to five outcomes, work is underway to consider how these should be measured. From 21 key stakeholder interviews, Hedrich (2004) original service model was updated, notably
incorporating experts-by-experience in the planning and evolution of the service. For a generic England setting, the epidemiological model projected: over 10 years an OPC can prevent 3.3-19% of fatal overdoses, 2.9-17% of
overdose-related ambulance calls, 5.2-27.3% of incident HCV infections, and 2.2-13.3% of SSTIs requiring emergency care/hospitalization, depending on OPC coverage, frequency of use, and whether additional prevention
benefits are conferred. The economic model suggested an OPC will generate a cost-benefit ratio of between £1.18- £1.44 for every pound spent on OPC operational costs over a 20 year period.
Outputs, impact and dissemination: Outputs complete/in production include two publications from the realist review, two papers/one report on the COS, two papers on the epidemiological and economic model, and three
papers on the service/implementation model. Following discussion with NIHR/delays in OPC establishment, we await the appropriate time to submit a PGfAR application.
Conclusions: We created tools for the evaluation of UK OPCs including an understanding of how they work, for whom, and in what circumstances; how they operate and a service model, and a framework for evaluation of
effectiveness and cost-effectiveness.
Future plans: To use this knowledge in the future evaluation of OPCs recognising the need for different models in different locations.