Background
pain
Embedded process evaluations of complex interventions in randomised controlled trials (RCTs) are critical to increase understanding of how and why interventions may or may not work, as well as how practical interventions are when implemented in service contexts. They increase confidence in trial results and provide guidance on their implementation.In the landmark Improving the Wellbeing of people with Opioid Treated CHronic pain (I-WOTCH) trial (n=608), we demonstrated that a self-management support intervention helps people using strong opioids become opioid-free at 1 year: 29% intervention versus 7% control, OR 6.55 (95% CI 3.42 to 12.55) with no increase in pain interference.The I-WOTCH intervention included educational, behavioural and psychological components, combining group and one-to-one support. Papers reporting the intervention development, the trial protocol, the main results and process evaluation protocol have been published.Experiences of the I-WOTCH intervention(s): including enablers of, and barriers to, change among participants.Implementation of the I-WOTCH group intervention: exploring the dose delivered and received, and the fidelity of delivery.Change mechanisms potentially underpinning intervention effects.Contextual issues: exploring how these may affect the outcome or running of the study and/or intervention.