Randomized Trial of Closed-Loop Control in Very Young Children with Type 1 Diabetes

N Engl J Med. 2022 Jan 20;386(3):209-219. doi: 10.1056/NEJMoa2111673.


Background: The possible advantage of hybrid closed-loop therapy (i.e., artificial pancreas) over sensor-augmented pump therapy in very young children with type 1 diabetes is unclear.

Methods: In this multicenter, randomized, crossover trial, we recruited children 1 to 7 years of age with type 1 diabetes who were receiving insulin-pump therapy at seven centers across Austria, Germany, Luxembourg, and the United Kingdom. Participants received treatment in two 16-week periods, in random order, in which the closed-loop system was compared with sensor-augmented pump therapy (control). The primary end point was the between-treatment difference in the percentage of time that the sensor glucose measurement was in the target range (70 to 180 mg per deciliter) during each 16-week period. The analysis was conducted according to the intention-to-treat principle. Key secondary end points included the percentage of time spent in a hyperglycemic state (glucose level, >180 mg per deciliter), the glycated hemoglobin level, the mean sensor glucose level, and the percentage of time spent in a hypoglycemic state (glucose level, <70 mg per deciliter). Safety was assessed.

Results: A total of 74 participants underwent randomization. The mean (±SD) age of the participants was 5.6±1.6 years, and the baseline glycated hemoglobin level was 7.3±0.7%. The percentage of time with the glucose level in the target range was 8.7 percentage points (95% confidence interval [CI], 7.4 to 9.9) higher during the closed-loop period than during the control period (P<0.001). The mean adjusted difference (closed-loop minus control) in the percentage of time spent in a hyperglycemic state was -8.5 percentage points (95% CI, -9.9 to -7.1), the difference in the glycated hemoglobin level was -0.4 percentage points (95% CI, -0.5 to -0.3), and the difference in the mean sensor glucose level was -12.3 mg per deciliter (95% CI, -14.8 to -9.8) (P<0.001 for all comparisons). The time spent in a hypoglycemic state was similar with the two treatments (P = 0.74). The median time spent in the closed-loop mode was 95% (interquartile range, 92 to 97) over the 16-week closed-loop period. One serious adverse event of severe hypoglycemia occurred during the closed-loop period. One serious adverse event that was deemed to be unrelated to treatment occurred.

Conclusions: A hybrid closed-loop system significantly improved glycemic control in very young children with type 1 diabetes, without increasing the time spent in hypoglycemia. (Funded by the European Commission and others; ClinicalTrials.gov number, NCT03784027.).

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Blood Glucose / analysis
  • Child
  • Child, Preschool
  • Cross-Over Studies
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Equipment Design
  • Female
  • Glycated Hemoglobin / analysis
  • Glycemic Control / instrumentation*
  • Glycemic Control / methods
  • Humans
  • Hyperglycemia / diagnosis
  • Hypoglycemic Agents / administration & dosage*
  • Infant
  • Insulin / administration & dosage*
  • Insulin Infusion Systems*
  • Male
  • Pancreas, Artificial*


  • Blood Glucose
  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • Insulin

Associated data

  • ClinicalTrials.gov/NCT03784027