Supporting continuous glucose monitoring for people with serious mental illness and type 2 diabetes: Protocol for a co-design study

Introduction Compared with the general population, people with serious mental illness (SMI) are 2-3 times more likely to develop type 2 diabetes, have poorer outcomes, and die 15 to 20 years younger, often as a result of long-term physical health conditions. Standard diabetes care does not meet the needs of people with SMI and they are frequently excluded from research, missing out on innovation. As diabetes care increasingly uses technology like continuous glucose monitoring (CGM) it is important to consider the views of people with SMI when new interventions are developed. This is a study protocol to identify candidate components of a structured CGM intervention for people with SMI, including the co-design of a logic model and programme theory. Methods Drawing on experience-based co-design (EBCD) methods, we propose to collaborate with service-users, carers, and healthcare professionals to undertake early-phase development work for a novel intervention that maximises the potential of CGM to facilitate behaviour change. Fifteen participants will be recruited through existing cohorts and networks in England. The co-design will be informed by existing evidence and based on links between mechanisms of action and behaviour change techniques. Through a series of events (discovery sessions, co-design workshop, celebration event), we will identify candidate components for a prototype intervention ready for further development and testing. A logic model and programme theory will be developed and refined iteratively. Discussion The main output of this study will be a logic model and programme theory for a novel prototype intervention, ready for further testing following best practice intervention development, such as the Medical Research Council guidance for the development and evaluation of complex interventions. An intervention that makes CGM accessible for people with SMI has the potential to make a considerable contribution to reducing the profound health inequalities experienced by this population. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Yes ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Department of Health Sciences, University of York, York, UK Research Governance Committee (HSRGC) approval obtained 9th April 2024. Reference number HSRGC/2024/616/G I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes No datasets were generated or analysed during the current study. All relevant data from this study will be made available upon study completion.