ESPE Yearbook of Paediatric Endocrinology

Diabetes TechnolTher. 2025. May 30. Online ahead of print. PMID: 40445776 doi: 10.1089/dia.2025.0062.

Brief summary: This two-center, randomized, crossover study assigned 24 adolescents (13-19 years) with type 1 diabetes (T1D) on insulin pump therapy and with above-target HbA1c to two 8-week periods of unrestricted living, comparing a fully closed loop (FCL) insulin delivery system to standard nonautomated insulin pump therapy with continuous glucose monitoring (CGM). The FCL system improved glucose outcomes and was safe.

Closed-loop systems have substantially changed the management of T1D in children and adolescents (1). However, these systems are primarily hybrid, requiring users’ input in certain situations, particularly at mealtimes. FCL systems, which eliminates the need for carbohydrate counting and pre-meal bolusing, have so far only been explored in a few clinical studies in adults with T1D or Type 2 diabetes (2,3). No data are available for adolescents with T1D, a population that struggles more than other age groups to achieve recommended HbA1c targets, even when using a closed-loop system (4). This is often due to missed or insufficient mealtime insulin doses (5).

This trial reports on the safety and efficacy of a FCL insulin delivery (CamAPS HX) in 24 adolescents with T1D and suboptimal glycemic outcomes, as indicated by a median HbA1c of 74 mmol/mol [8.9%], under unrestricted living conditions, using a cross-over design. FCL use was safe and led to a better percentage of time with glucose in target range (TIR) (primary endpoint 3.9-10.0 mmol/l) compared to nonautomated pump (45.2% vs. 32.3%), and lower time spent in hyperglycemia (time above range, TAR) (>13.9 mmol/l) (28.7% vs. 39.6%). The achieved TIR in the FCL group was below the recommended target (>70%), but was much better than the baseline value (37%). No differences were found in the percentage of time spent in the hypoglycemia range (glucose <3.9 mmol/l), Hb1Ac and total daily insulin dose.

Although the study was limited by a small sample size, short duration (8 weeks), and recruitment from only two UK clinical sites, the findings are nonetheless encouraging. FCL systems may offer a novel approach to improveglycemic outcomes and reduce diabetes-related distress in the vulnerable adolescent population with T1D.

References: 1. Royston C, Hovorka R, Boughton CK (2025) Closed-loop therapy: recent advancements and potential predictors of glycemic outcomes. Expert Opin Drug Deliv 22(6): 875-892.2. Boughton CK, Hartnell S, Lakshman R, et al. (2023) Fully Closed-Loop Glucose Control Compared With Insulin Pump Therapy With Continuous Glucose Monitoring in Adults With Type 1 Diabetes and Suboptimal Glycemic Control: A Single-Center, Randomized, Crossover Study. Diabetes Care 46(11): 1916-1922.3. Daly AB, Boughton CK, Nwokolo M, et al. (2023) Fully automated closed-loop insulin delivery in adults with type 2 diabetes: an open-label, single-center, randomized crossover trial. Nat Med 29(1): 203-208.4. Ebekozien O, Mungmode A, Sanchez J, et al. (2023) Longitudinal Trends in Glycemic Outcomes and Technology Use for Over 48,000 People with Type 1 Diabetes (2016-2022) from the T1D Exchange Quality Improvement Collaborative. Diabetes Technol Ther 25(11): 765-773.5. Olinder AL, Kernell A, Smide B (2009) Missed bolus doses: devastating for metabolic control in CSII-treated adolescents with type 1 diabetes. Pediatr Diabetes 10(2): 142-148.