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Original Investigation
October 11, 2021

Effect of a Hybrid Closed-Loop System on Glycemic and Psychosocial Outcomes in Children and Adolescents With Type 1 Diabetes: A Randomized Clinical Trial

Author Affiliations
  • 1Children’s Diabetes Centre, Telethon Kids Institute, University of Western Australia, Perth, Australia
  • 2Department of Endocrinology and Diabetes, Perth Children’s Hospital, Perth, Australia
  • 3Division of Paediatrics, University of Western Australia Medical School, Perth, Australia
  • 4Department of Endocrinology and Diabetes, Women’s and Children’s Hospital, Adelaide, Australia
  • 5Department of Endocrinology and Diabetes, John Hunter Children’s Hospital, Newcastle, Australia
  • 6Institute of Endocrinology and Diabetes, Children’s Hospital at Westmead, University of Sydney, Sydney, Australia
  • 7Department of Endocrinology and Diabetes, Royal Children’s Hospital, Melbourne, Australia
  • 8Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
  • 9Department of Endocrinology and Diabetes, St Vincent's Hospital, Melbourne, Victoria, Australia
  • 10National Health and Medical Research Council Clinical Trials Centre, Faculty of Medicine and Health, University of Sydney, Australia
JAMA Pediatr. Published online October 11, 2021. doi:10.1001/jamapediatrics.2021.3965
Key Points

Question  For children and adolescents with type 1 diabetes, does a hybrid closed-loop (HCL) system improve glycemic and psychosocial outcomes compared with conventional management?

Findings  In this 6-month randomized clinical trial including 135 children and adolescents, mean percent time in target glucose range was 62.5% with HCL therapy and 56.1% with standard therapy with a mean adjusted difference of 6.7%. Diabetes-specific quality of life was higher with HCL therapy than with standard therapy.

Meaning  The HCL system improved glycemic control and quality of life compared with conventional diabetes management in youth with type 1 diabetes.


Importance  Hybrid closed-loop (HCL) therapy has improved glycemic control in children and adolescents with type 1 diabetes; however, the efficacy of HCL on glycemic and psychosocial outcomes has not yet been established in a long-term randomized clinical trial.

Objective  To determine the percentage of time spent in the target glucose range using HCL vs current conventional therapies of continuous subcutaneous insulin infusion or multiple daily insulin injections with or without continuous glucose monitoring (CGM).

Design, Setting, and Participants  This 6-month, multicenter, randomized clinical trial included 172 children and adolescents with type 1 diabetes; patients were recruited between April 18, 2017, and October 4, 2019, in Australia. Data were analyzed from July 25, 2020, to February 26, 2021.

Interventions  Eligible participants were randomly assigned to either the control group for conventional therapy (continuous subcutaneous insulin infusion or multiple daily insulin injections with or without CGM) or the intervention group for HCL therapy.

Main Outcomes and Measures  The primary outcome was the percentage of time in range (TIR) within a glucose range of 70 to 180 mg/dL, measured by 3-week masked CGM collected at the end of the study in both groups. Secondary outcomes included CGM metrics for hypoglycemia, hyperglycemia, and glycemic variability and psychosocial measures collected by validated questionnaires.

Results  A total of 135 patients (mean [SD] age, 15.3 [3.1] years; 76 girls [56%]) were included, with 68 randomized to the control group and 67 to the HCL group. Patients had a mean (SD) diabetes duration of 7.7 (4.3) years and mean hemoglobin A1c of 64 (11) mmol/mol, with 110 participants (81%) receiving continuous subcutaneous insulin infusion and 72 (53%) receiving CGM. In the intention-to-treat analyses, TIR increased from a mean (SD) of 53.1% (13.0%) at baseline to 62.5% (12.0%) at the end of the study 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 = .002). Hybrid closed-loop therapy also reduced the time that patients spent in a hypoglycemic (<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%). Hybrid closed-loop 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.

Conclusions and Relevance  In this randomized clinical trial, 6 months of HCL therapy significantly improved glycemic control and quality of life compared with conventional therapy in children and adolescents with type 1 diabetes.

Trial Registration  ANZCTR identifier: ACTRN12616000753459

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