Endocrine Abstracts

Introduction: Hybrid closed loop pumps (HCL) incorporate insulin pumps (IPs) with continuous glucose monitoring (CGM). Basal and bolus insulin release can be algorithmically adjusted in real-time enabling some automated insulin changes between meals according to set parameters. We reviewed the glycaemic control of patients with T1D cared for at the Evelina who had upgraded from IP to HCL between October 2020 and January 2022.

Methods: As per standard care, patients were reviewed in clinic every 3 months and HbA1c was measured, and time in range (TIR) reviewed using CGM data. In between visits pump downloads were reviewed to optimise IP settings. Patients selected were upgraded when they were eligible for a new pump (pump warranty is 4years) if they wished to embrace the new technology. When upgrading, patients and their parents/carers were instructed on HCL use by a diabetes professional.

Results: Overall, 13 patients had been upgraded, from which 9 (6 male) fell within the date range and had sufficient data for analysis. Median age was 10 years (range, 6-16). Mean HbA1c values were calculated for each patient before and after upgrade and TIR reviewed. The mean HbA1c of the group before HCL was 7.640% (60 mmol/mol), SD +/-0.484%, and after HCL was 6.919% (52 mmol/mol), SD +/- 0.244%. A single-tailed paired t-test was used to compare the HbA1c values, giving a t-value of 3.99 (16 DoF), showing a P-value of <0.0003. Mean time in range (TIR) was calculated before upgrade 53.5%, SD +/-10.94% and afterwards 68%, SD +/-7.34%, with a P-value of 0.0019.

Conclusions: Our review shows a significant improvement in glycaemic control following a switch from a simple IP to a HCL in our paediatric patients with T1D. Of note these patients had reasonable diabetes control before the switch but were able to make significant improvements having made the switch. However this is a small sample size, and so should be investigated further with a larger sample, ideally incorporating some quality of life data.