Trial Details Efficacy of Long-term HCL Therapy in Pediatric Patients With T1D

Researchers conducted a randomized clinical trial to test the efficacy of a hybrid closed-loop (HCL) system in pediatric patients with type 1 diabetes (T1D).

Six months of hybrid closed-loop (HCL) therapy significantly improved glycemic control and quality of life in children and adolescents with type 1 diabetes (T1D) compared to conventional therapy, according to the results of a randomized clinical trial. The findings were published in JAMA Pediatrics.

“The HCL system uses a control algorithm that delivers insulin based on continuous glucose monitoring (CGM) glucose measurements,” the authors explained. “Meals, however, still need to be announced and an insulin bolus should be administered based on the carbohydrate content of the meal.” Previous research found that this system improved glycemic measures, compared to standard therapy, in adults with T1D.

To evaluate the long-term efficacy of the HCL in children and adolescents with T1D and to address the psychosocial outcomes of use, researchers conducted a 6-month trial in Australia. Specifically, they compared the percentage of time in range (TIR) ​​for the target glucose range (70 to 180 mg/dL) using HCL versus currently available conventional therapies (continuous subcutaneous insulin infusion). [CSII] or multiple daily injections [MDI] with or without CGM).

Between April 2017 and October 2019, researchers recruited 135 patients from 5 tertiary pediatric diabetes centers in Australia. After a 5-week run-in phase, participants were randomly assigned to the control or intervention (HCL) groups for 26 weeks. In addition, masked CGM data were collected at baseline (3 weeks), midudy (2 weeks), and study end (3 weeks), researchers said.

The mean (SD) age of the participants was 15.3 (3.1) years and the majority were girls (56%). Sixty-eight patients were randomized to the control group and 67 to the HCL group, while patients had a mean diabetes duration of 7.7 (4.3) years and a mean glycated hemoglobin (HbA1C) of 64 (11) mmol/mol.

Analyzes revealed:

In the intention-to-treat analyses, TIR increased from an average of 53.1% (13%) at baseline to 62.5% (12%) at study end in the HCL group and from 54.6 % (12.5%) to 56.1% (12.2%) in the control group, with a mean adjusted difference between the 2 groups of 6.7% (95% CI, 2.7%-10.8% p = 0.002) This mean difference corresponded to an additional 1.6 hours per day in target range on HCLHCL therapy also reduced the time patients spent in a hypoglycaemic (<70 mg/dL) range (difference, −1.9% 95% CI, − 2.5% to − 1.3%) and improved glycemic variability (coefficient of variation difference, −5.7%; 95% CI, −10.2% to −0.9%) HCL therapy was associated with improved diabetes-specific quality of life (difference, 4.4 points; 95% CI, 0.4-8.4 points), with no change in diabetes distress There were no episodes of severe hypoglycemia or diabetic ketoacidosis in either group

“In our study, the improvement in TIR was observed both during the day and at night and was associated with a reduction in hypoglycemia and glycemic variability, albeit without a reduction in hyperglycemia,” the authors wrote.

Researchers hypothesized that improved quality of life scores reported with HCL use may be due to factors such as reduced worry, increased trust and confidence in the system with improved glycemic control, and increased ownership of diabetes management.

Since the trial was conducted by tertiary centers with technological expertise, the results may not be generalizable to the general public, which is a limitation. In addition, researchers were unable to assess the degree of involvement with CGM devices of participants in the control group.

“To our knowledge, this is the first randomized clinical trial in adolescents with T1D to provide compelling evidence that HCL improves glycemic outcomes and quality of life in adolescents with T1D,” the authors concluded. “The HCL system represents an important step in the pursuit of technological progress towards a fully automated closed loop system.”


Abraham MB, de Bock M, Smith GJ, et al. Effect of a hybrid closed-loop system on glycemic and psychosocial outcomes in children and adolescents with type 1 diabetes: a randomized clinical trial. JAMA Pediatrician. Published online October 11, 2021. doi:10.1001/jamapediatrics.2021.3965

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