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Am Fam Physician. 2022;106(1):online

Clinical Question

Does a closed-loop system offer benefits over sensor-augmented pump therapy in children one year to seven years of age?

Bottom Line

A closed-loop system that automatically adjusts the delivery rate of an insulin pump increases the time in the target glucose range without any other measurable benefits over the short study period. There may be quality of life benefits for parents and children because of less need for hands-on decision-making, but in this study there was one episode of severe hypoglycemia. This seems like an opportunity for shared decision-making. (Level of Evidence = 1b−)


Sensor-augmented pump therapy uses continuous monitoring of blood glucose combined with an insulin pump. A closed-loop system (sometimes called an artificial pancreas) takes the human out of the loop and uses an algorithm to adjust insulin delivery. The authors identified 74 children, one year to seven years of age, who had type 1 diabetes mellitus for at least six months and a glycated hemoglobin level of 11% or lower. Those 74 children were randomized into two groups. The mean age of the children was 5.6 years, the two groups were balanced at the beginning of the study, and the analysis was by intention to treat. Group A began with the closed-loop system; group B began with the sensor-augmented pump therapy. After 16 weeks, they had a one- to four-week washout period before they crossed over to receive the other therapy for 16 weeks. During the closed-loop period, children were more likely to be in the target glucose range of 70 to 180 mg per dL (3.89 to 9.99 mmol per L; 71.6% vs. 62.9%; P < .001; number needed to treat = 11) and their mean glycated hemoglobin level was a bit lower (6.4% vs. 7.0%; P < .001). There was no difference in the time spent with low blood sugar (defined as less than 54 mg per dL [3.0 mmol per L], 63 mg per dL [3.5 mmol per L], or 70 mg per dL) or insulin use, and only a very small reduction in the percentage of time spent with a glucose level higher than 300 mg per dL (16.65 mmol per L; 2.0% vs. 3.1%; 95% CI for the difference, −1.6% to −0.6%). Overall adverse events were similar, but there was one severe episode of hypoglycemia in the closed-loop group compared with zero in the sensor-augmented pump therapy group.

Study design: Crossover trial (randomized)

Funding source: Government

Allocation: Concealed

Setting: Outpatient (specialty)

Reference: Ware J, Allen JM, Boughton CK, et al.; KidsAP Consortium. Randomized trial of closed-loop control in very young children with type 1 diabetes. N Engl J Med. 2022;386(3):209-219.

Editor's Note: Dr. Ebell is deputy editor for evidence-based medicine for AFP and cofounder and editor-in-chief of Essential Evidence Plus, published by Wiley-Blackwell.

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