American Diabetes Association
2 files

Effect of 48 months of closed-loop insulin delivery on residual C-peptide secretion and glycemic control in newly diagnosed youth with type 1 diabetes: a randomized trial

posted on 2024-06-26, 20:40 authored by Julia Ware, Charlotte K. Boughton, Janet M. Allen, Malgorzata E Wilinska, Sara Hartnell, Ajay Thankamony, Tabitha Randell, Atrayee Ghatak, Rachel E.J. Besser, Daniela Elleri, Nicola Trevelyan, Fiona M. Campbell, Judy Sibayan, Ryan Bailey, Peter Calhoun, Gareth Dunseath, Roman Hovorka


We evaluated the effect of long-term intensive metabolic control with hybrid closed‑loop on residual C-peptide secretion and glucose control compared to standard insulin therapy in youth with type 1 diabetes over 48 months.

Research Design and Methods

Following the 24-month primary phase of a multicenter, randomized, parallel trial of 96 newly diagnosed youth aged 10 to 16.9 years, participants were invited to an extension phase using treatment allocated at randomization. They continued with either hybrid closed-loop using Cambridge algorithm (CL) or standard insulin therapy (control) until 48 months post-diagnosis. Analysis was by intention-to-treat.


At 24-months post-diagnosis, 81 participants (mean±SD age 14±2 years) continued in the extension phase (47 CL, 34 control). There was no difference in fasting C-peptide corrected for fasting glucose at 48 months between groups (CL: 5±9 vs control: 6±14pmol/L per mmol/L; mean adjusted difference -2 [95% CI -7, 4; p=0.54]). Central lab HbA1c remained lower in the CL group by 0.9% [10mmol/mol] (95% CI 0.2, 1.5 [3, 17mmol/mol]; p=0.009). Time in target range 3.9 to 10.0mmol/L was 12 percentage points (95% CI 3, 20; p=0.008) higher in the CL group compared to control. Eleven severe hypoglycemic events (6 CL, 5 control) and seven DKA events (3 CL, 4 control) occurred during the extension phase.


Improved glycemic control was sustained over 48 months after diagnosis with closed‑loop insulin delivery compared to standard therapy in youth with type 1 diabetes. This did not appear to confer a protective effect on residual C-peptide secretion.


This work was funded by the Helmsley Trust (2016PG-T1D045 and 2016PG-T1D046), NIHR EME (14/23/09) and JDRF (22-2013-266 and 2-RSC-2019-828-M-N). Additional support for the artificial pancreas work from National Institute for Health Research Cambridge Biomedical Research Centre and National Institute for Health Research Oxford Biomedical Research Centre. Abbott Diabetes Care supplied free glucose monitoring devices, and Dexcom supplied discounted continuous glucose monitoring devices. Medtronic supplied discounted insulin pumps, phone enclosures, continuous glucose monitoring devices, and pump consumables. The views expressed are those of the author(s) and not necessarily those of the funders.


Usage metrics

    Diabetes Care


    Ref. manager