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Hybrid Closed-Loop Insulin Delivery for Children

Nov 10, 2020
Editor: Steve Freed, R.PH., CDE

Author: Zahra Hashemy, PharmD. Candidate, USF Taneja College of Pharmacy 

Young children with type 1 diabetes often experience greater insulin variability, leading to more complications and a subpar quality of life; can a closed-loop insulin delivery system help?

Age can play a significant factor in insulin variability. Children’s activities, developmental and hormonal changes can cause challenges with delivering insulin based on treatment goals. Hybrid closed-loop devices are a step above continuous injections and monitoring devices that need the user to determine the amount of insulin needed to be delivered at each delivery. Hybrid closed-loop devices deliver insulin autonomously by using an algorithm that sensors glucose values in real-time; standard delivery by the user is only given for boluses at the time of a meal.  


This study aims to determine the relationship between insulin variability and age, which has yet to be determined. Investigators sought to observe if insulin variability was higher amongst the younger population. This retrospective multicenter study observed 114 patients age 1-65 years old in an unrestricted lifestyle for three weeks while using a hybrid closed-loop device. The inclusion criteria for the study were as follows: a minimum of 6 months’ diagnosis of type 1 diabetes as approved by the World Health Organization (WHO), the use of insulin pump for >3 months, <2 IU/kg/day for a total daily dose of insulin. The different studies observed had differing threshold upper and lower limits for glycated hemoglobin, with the highest upper limit being 11% (97mmol/mol), and the lower limit 7.5% (58.5 mmol).  An informed consent form was signed by the study participants and their parents or caregiver.  

Participants were stratified into four groups: young children ages 1-6 years old, children ages 7-12 years old, adolescents ages 13-17 years old, and adults 18 years and older. Pairwise comparisons were made with the one-way ANOVA with post hoc analysis through the Tukey test. SPSS was used to perform statistical analysis. The coefficient change of insulin variation was observed at night between midnight and 5:59 am and at daytime between 6:00 am and 23:59. Two closed-loop prototype devices, FlorenceM and FlorenD2A, were utilized. Both prototypes used a treat-to-target control algorithm that communicated with a smartphone. Participants were thoroughly trained on using the devices during the one to four-week run-in period of the study. 

Data of 2,336 nights showed that the coefficient variation of insulin delivered during the night was 10.7% higher in young children than adults (95% CI 2.9-18.4, p=0.003) and 10.2 % higher than adolescents (95% CI 0.0-20.4 P- 0.049). Data over 2,367 days showed that the coefficient measuring insulin variation was 6.4% higher in young children than adults (95% Ci 2.0-10.9%, P=0.2) and 7.0% higher than adolescents (95% CI 1.1.-12.8%, P=0.014). 

Parents and caregivers often worry that their child will experience dysglycemia and be more prone to nighttime hypoglycemia despite regular insulin dose adjustments. The pumps provided alerts for hypoglycemic and hyperglycemic episodes. The data observed in this study provides information as to why young children with type 1 diabetes often experience more complications leading to a quality of life that is subpar. A hybrid closed-loop insulin device can alleviate the stress associated with standard insulin delivery. The control-treat algorithm of the device will provide insulin as needed while the child sleeps. 

The results of this study can be applied to the general population, given the variety of participants. The study population included multiple nationalities, including the U.S., U.K., Germany, and Austria. Ages ranged from pediatrics to the elderly. There was no restriction of lifestyle or pre-determined lifestyle change implemented in the study. The study’s limitations include using two closed-loop devices systems and the differences in study measurements between the studies included. Although people of all ages can use hybrid closed-loop systems, this study is vital in providing data for young children’s benefits. This study had a short follow up-time; a clinical trial with a long follow-up time would be vital in providing substantial data to support closed-loop devices in delivering insulin for young children with type 1 diabetes.   

Practice Pearls: 

  • Young children have a higher variability of insulin requirements compared to adolescents and adults 
  • Level of activity, the time when food is consumed, types of food consumed, and other variables can cause a variance in insulin delivery from night to night and day to day. 
  • Hybrid closed-loop insulin delivery systems can remove the burden of continual insulin adjustments to meet treatment goals. 


DovcKlemen et al. “Young Children Have Higher Variability Of Insulin Requirements: Observations During Hybrid Closed-Loop Insulin Delivery.” Diabetes Care, vol 42, no. 7, 2019, pp. 1344-1347.   


Zahra Hashemy, PharmD. Candidate, USF Taneja College of Pharmacy