Adult persons with type 2 diabetes and family engagement in diabetes self-management education and support: what works, for whom, under what circumstances and how? – a realist review protocol

Introduction Diabetes self-management education and support (DSME/S) programmes must demonstrate effective engagement of family members to achieve diabetes self-management outcomes and well-being of the whole family. These are complex interventions and their effectiveness is context dependent. We present initial programme theories of DSME/S and aim to answer: In what contexts and through which mechanisms do DSME/S interventions involving family caregivers impact diabetes self-management outcomes?Methods and analysis The review will follow the Realist and Meta-narrative Evidence Syntheses: Evolving Standards and Pawson’s five steps: define the scope, develop initial programme theories, search for evidence, appraise studies and extract and synthesise data. Literature searching will be combined with feedback from patient and public involvement stakeholders. PubMed, EMBASE, CINAHL, Scopus and PsycINFO will be searched to February 2026, with citation tracking and grey literature included. Data will be synthesised inductively to develop programme theories and context–mechanism–outcome configurations.Ethics and dissemination This study is a realist synthesis protocol and does not require ethics approval. The study will use published evidence and grey literature with contributions from patient and public involvement stakeholders. The study will produce transferrable programme theories that explain the contexts and mechanisms that influence DSME/S intervention impact and the considerations required to maximise family involvement in diabetes care. These programme theories will provide conceptual frameworks for consideration when designing DSME/S interventions for various contexts in order to maximise self-management capabilities of the persons with diabetes while promoting the health of the family as a whole. Findings will be published in peer-reviewed journals and presented at scientific conferences.PROSPERO registration ID CRD420251179485.