Closed-Loop from Diagnosis of Type 1 Diabetes in Children and Young People

To the Editor,

Two randomized controlled trials investigating closed-loop from diagnosis of type 1 diabetes (T1D) in children and young people have been published recently. ^1,2 Although these studies consistently refute the hypothesis that improving glucose control soon after diagnosis preserves endogenous insulin secretion, clinically important improvements in glucose control are observed with closed-loop technology.

Between-group differences in glucose control between those using closed-loop and those receiving standard care start to appear 6–9 months after diagnosis. Glycemia in those receiving standard care starts to deteriorate and is already above target by 12 months. In the Closed-Loop From Onset in Type 1 Diabetes (CLOuD) study, HbA1c at 12 months in the control group was 7.3% [56 mmol/mol] compared with 6.9% [52 mmol/mol] in the closed-loop group (time in range 64% vs. 54%) and continued to deteriorate further by 24 months (HbA1c in the control group 8.0% [63 mmol/mol] compared with 6.9% [52 mmol/mol] in the closed-loop group) (time in range 64% vs. 49%). ¹

Conversely, glycemic control in the closed-loop group remained stable over 24 months post-diagnosis. A similar trend was reported in the Hybrid Closed-Loop Therapy and Verapamil for Beta Cell Preservation in New Onset Type 1 Diabetes (CLVer) trial. ² Glycemic differences occurred despite high use of glucose sensors and insulin pump technology in the standard care group.

Modeling data from the Epidemiology of Diabetes Interventions and Complications (EDIC) study cohort suggests beneficial effects of earlier versus later implementation of intensive therapy in T1D. ³ Earlier implementation is associated with a greater reduction in the risks of kidney and cardiovascular complications compared with later implementation, despite both groups having the same average glycemic exposure over the entire period, highlighting the importance of utilizing therapies that allow tight glycemic control from as early as possible in T1D.

Hybrid closed-loop insulin delivery appears to be safe when used from diagnosis and throughout the “honeymoon period” in children and adolescents with T1D. These glucose responsive systems can effectively manage the variability of exogenous day-to-day insulin requirements during the period when there is declining residual endogenous insulin secretion and can achieve stable glycemic control.

Glycemic control tends to deteriorate during adolescence due to challenging physiological factors, including growth and puberty, behavioral, and psychological factors. Data from the CLOuD study show that consistent glycemic control was achieved over 24 months with closed-loop in this population. This is despite relatively low diabetes management burden with on average 10 min per day spent within app checking glucose levels, delivering insulin boluses, and responding to alarms. ⁴ This suggests that closed-loop may mitigate some of the challenges associated with managing T1D in adolescence.

Interviews of CLOuD participants using closed-loop therapy captured important benefits of this technology on quality of life. ⁵ Participants reported few disruptions to their lives when using closed-loop technology. Adolescents described doing normal activities without worrying about high or low glucose levels, and parents reported allowing them to do so unsupervised because of closed-loop managing their glucose and keeping them safe.

We advocate that closed-loop systems should be used from diagnosis of T1D in children and adolescents as the glycemic benefits are clinically important, and the associated improvements in quality of life and diabetes burden may help to mitigate the deterioration of glycemic control that occurs in this population.