Older Adult Closed Loop (ORACL) Study for Type 1 Diabetes

This randomised crossover study compares closed-loop (CL) therapy versus open-loop (OL) therapy (with insulin pump and real-time continuous glucose monitoring (CGM)) for older adults with type 1 diabetes. This study will consist of 12 visits over approximately 9-11 months. Duration of visits will be up to 6 hours to provide participant education and collect study outcome data. All procedures involving study participants will be undertaken by study doctors, research nurses, dietitians and psychologists. Participants will be provided with study devices and will receive face-to-face education regarding their use. Clinician researchers will determine when educational requirements have been completed. The study intervention is an insulin delivery system, that has CL capability to continuously deliver automated subcutaneous insulin doses via a cannula placed transcutaneously. The CL system comprises a CGM device (with transcutaneous glucose sensor filament connected to an external recorder), coupled with an insulin pump containing a computerised automated insulin delivery algorithm. Glucose sensor information is transmitted to the insulin pump, and the dose of insulin is calculated by the algorithm and automatically delivered every 5 minutes to account for basal insulin requirements. User-initiated bolus insulin doses are required for meals. Intervention adherence and function will be assessed via pump upload. The study involves a run-in period for education and collection of pre-randomisation data (up to 10 weeks depending on individual participant educational requirements), pre-randomisation measures (2 weeks), randomisation, followed by two 4-month study stages undertaken in random order. The stages are (i) CL with automated basal insulin delivery, and (ii) OL with manual insulin delivery via pump and real-time CGM. There will no wash-out period between stages.