Real-world outcomes of hybrid closed-loop insulin pump therapy in UK children and young people with type 1 diabetes and high HbA1c: a multicentre retrospective cohort study

OBJECTIVE: To evaluate changes in glycated haemoglobin (HbA1c) following initiation of hybrid closed-loop (HCL) insulin pump therapy in children and young people (CYP) with previously elevated HbA1c in a real-world multicentre setting. DESIGN: Retrospective multicentre observational cohort study. SETTING: 13 National Health Service paediatric diabetes units within a regional diabetes network in England, UK. PATIENTS: CYP aged ≤19 years with type 1 diabetes of more than 1 year's duration and HbA1c ≥69 mmol/mol at the time of HCL initiation and at least 3 months prior. INTERVENTIONS: Initiation of HCL insulin pump therapy. MAIN OUTCOME MEASURES: Primary outcome was change in HbA1c following HCL initiation. Secondary outcomes included subgroup and pump system comparisons and changes in diabetes-related hospital admissions. RESULTS: A total of 220 participants were included. HbA1c decreased significantly following HCL initiation (p<0.001), falling from a mean of 82.5 mmol/mol at baseline to 72.8 mmol/mol within the first 3 months and remaining stable thereafter with a mean value of 69.3 mmol/mol at 12 months. Improvements were observed across all subgroups, with the greatest reductions in those with very high baseline HbA1c (>100 mmol/mol) and in participants transitioning from multiple daily injections. Outcomes were similar across HCL pump systems, and diabetes-related hospital admissions decreased overall following HCL initiation. CONCLUSIONS: In this large, real-world cohort of CYP with high HbA1c, initiation of HCL therapy was associated with sustained improvements in glycaemic control and fewer diabetes-related hospital admissions, supporting its use in this high-risk population.