Sustained 3-Year Improvement of Glucose Control With Hybrid Closed Loop in Children With Type 1 Diabetes While Going Through Puberty

To evaluate the impact of prolonged hybrid closed loop (HCL) use in children with type 1 diabetes (T1D) on glucose control and BMI throughout pubertal progression.

We used a prospective multicenter extension study following the Free-Life Kid AP (FLKAP) HCL trial. The 9-month previously reported FLKAP trial included 119 prepubertal children (aged 6–12 years). During the extension study, participants could continue to use HCL for 30 months (M9 to M39). HbA_1c values were collected every 3 months up to M39, while continuous glucose monitoring metrics, BMI z scores, and Tanner stages were collected up to M24. Noninferiority tests were performed to assess parameter sustainability over time.

One hundred seventeen children completed the extension study, with mean age 10.1 years (minimum to maximum, 6.8–14.0) at the beginning. Improvement of HbA_1c obtained in the FLKAP trial was significantly sustained during extension (median [interquartile range], M9 7.0% [6.8–7.4], and M39 7.0% [6.6–7.4], P < 0.0001 for noninferiority test) and did not differ between children who entered puberty at M24 (Tanner stage ≥2; 54% of the patients) and patients who remained prepubertal. BMI z score also remained stable (M9 0.41 [−0.29 to 1.13] and M24 0.48 [−0.11 to 1.13], P < 0.0001, for noninferiority test). No severe hypoglycemia and one ketoacidosis episode not related to the HCL system occurred.

Prolonged use of HCL can safely and effectively mitigate impairment of glucose control usually associated with pubertal progression without impact on BMI in children with T1D.