Understanding the contextual factors that impact on the effective provision of Opiate Substitution Therapy (OST) and Needle and Syringe Programmes (NSP) in the UK

Many people who inject drugs (PWID) experience serious harms including blood borne viruses (hepatitis C and HIV) and deaths from drug overdose.

Some groups of PWID (such as people who are older, younger, new to injecting, homeless, stimulant users and those out of treatment) are at more risk of harm and are the focus of this study.

Two main harm reduction services in the UK are needle exchanges and opioid substitution treatment (OST) (usually methadone). Although we know that both services can reduce harms, there are concerns over whether they are being delivered, and used, in ways that make them most effective and best value for money.

Knowing more about what makes these services more effective could prevent more harms and deaths.

This 24-month study has 3 stages:

• First, a review of published literature to provide evidence on what helps or hinders effective delivery and use of these services.
• Next, an online survey of UK drug service commissioners to find out how OST and needle exchanges are provided, to whom, and using which models of delivery to help identify what services are provided across the UK, using which models and what gaps in services exist.
• Third, a 'realist evaluation' to understand what service provision models work best, for which high risk groups of PWID and why.

We will interview up to 52 PWID and up to 56 service staff in 4 study sites across the UK. We will ask people we interview about what helps and hinders the delivery or use of services in terms of access, engagement and retention. We will also ask people about the cost of services including their use by PWID and examine some routine service data allowing us to find out the best value way to improve the impact of these services for PWID.

We will involve PWID in all aspects of the study and disseminate study results widely.