Protocol for the Diabetes Technology Network UK and Association of British Clinical Diabetologists' closed-loop insulin delivery audit programme

Background: The Association of British Clinical Diabetologists (ABCD) closed-loop audit aims to capture real-world out- comes from all who use hybrid closed-loop (HCL) insulin delivery systems in routine clinical care. In addition, NHS England has announced a pilot programme this year to expand access to HCL insulin delivery systems to people with type 1 diabetes (T1D) who are already using pump therapy and FreeStyle Libre with a HbA1c ≥ 69mmol/mol (≥ 8.5%). This group is often underrepresented in current randomised control trial evidence and, vitally, the planned audit will capture their data. Methods: The ABCD nationwide audit programme has Caldicott guardian approval and has also been approved by Confidentiality Advisory Group (CAG). Clinical teams collect anonymised user data using a secure online tool. Baseline characteristics and routinely collected outcome data at follow-up will include: assessment of glycaemic outcomes ( HbA1c, time in range, time below range); patient-reported outcome measures (Gold score and diabetes-related distress); and frequency of resource utilisation (hospital admissions, paramedic callouts, diabetic ketoacidosis [DKA] and severe hypoglycaemia). Discussion: The ABCD closed-loop audit will produce an inde- pendent real-world dataset of outcomes in closed-loop users across multiple systems. These data will provide insight into the real-world benefits and challenges of HCL systems used within the NHS in England.