Impact of health system engagement on the health and well-being of people who use drugs: a realist review protocol

Although community-level benefits of health system engagement (i.e., health service planning, delivery, and quality improvement, engaged research and evaluation, and collaborative advocacy) are well established, individual-level impacts on the health and well-being of community members are less explored, in particular for people who use or have used illegal drugs (PWUD). Capacity building, personal growth, reduced/safer drug use, and other positive outcomes may or may not be experienced by PWUD involved in engagement activities. Indeed, PWUD may also encounter stigma and harm when interacting with healthcare and academic structures. Our objective is to uncover why, how, and under what circumstances positive and negative health outcomes occur during health system engagement by PWUD. We propose a realist review approach due to its explanatory lens. Through preliminary exploration of literature, lived experience input, and consideration of formal theories, an explanatory model was drafted. The model describes contexts, mechanisms, and health outcomes (e.g., mental health, stable/safer drug use) involved in health system engagement. The explanatory model will be tested against the literature and iteratively refined against formal theories. A participatory lens will also be used, wherein PWUD with lived experience of health system engagement will contribute throughout all stages of the review. We believe this is the first realist review to explore the contextual factors and underlying mechanisms of health outcomes for PWUD who participate in health system engagement. A thorough understanding of the relevant literature and theoretical underpinnings of this process will offer insights and recommendations to improve the engagement processes of PWUD.