Endocrine Abstracts

Introduction: Hybrid closed-loop (HCL) systems improve time in range (TIR, 3.9-10.0 mmol/l) in children with type 1 diabetes (T1D). However, real-world data across different age groups is lacking.

Objectives: Evaluate glucose metrics in children with T1D using HCL systems, categorised by age groups.

Methods: Retrospective analysis (2019-2024) of children switching from continuous glucose monitoring (CGM) to HCL at a single tertiary centre. Data on demographics, CGM metrics and insulin were collected from databases, in CYP with >50% data capture. 90-day CGM data before and after HCL were compared.

Results: 169 CYP (53% male) with mean age of 12.4 (±3.6) years and T1D duration of 6.0 (±3.7) years were included. Categorised by age in years, 6% (n = 11) were <5 (G1), 34% (n = 57) were 5-11 (G2), and 60% (n = 101) were ≥12 (G3). On CGM, time below range (TBR, <3.9 mmol/l) (1.6%, 2.1%, 2.2%, P = 0.598), TIR (43%, 46%, 50%, P = 0.078), and mean blood glucose (MBG mmol/l) (11.4, 11.0, 10.5, P = 0.151) did not show any statistically significant difference between G1, G2 and G3, respectively. On HCL, TBR (3.3%, 2.1%, 1.8%, P < 0.05) was different for G1, G2 and G3, respectively, with G1 being higher than G3 (P < 0.01). TIR (63%, 65%, 65%, P = 0.764), and MBG mmol/l (9.1, 9.2, 9.2, P = 0.933) were comparable for G1, G2 and G3, respectively. Following switch to HCL the change in TBR was higher in G1 (1.6%) when compared to G2 (0.2%, P < 0.05) and G3 (-0.5%, P < 0.05). No differences were found for change in TIR (21%, 19%, 15%, P = 0.098), and MBG mmol/l (-2.3, -1.8, -1.4, P = 0.056) for G1, G2 and G3, respectively. Over 90-days of HCL; daily meal entries for G3 (3.6) were significantly lower than G1 (5.2, P < 0.001) and G2 (4.6, P < 0.001). Mean total daily insulin units over 90-days of HCL for G1 (10.2) was significantly lower than G2 (33.2, P < 0.001) and ≥12 (54.5, P < 0.001).

Conclusions: HCL systems achieve equivalent TIR, TAR and MBG improvements in children of different ages. However, transitioning to HCL results in more hypoglycaemia for children under five years, possibly due to more frequent meals and algorithmic insensitivity to low daily insulin doses.