Over the past few years, we’ve been reporting on developments in an exciting new diabetes technology called the “closed-loop” system. What is a closed-loop system? It’s sometimes described as an artificial pancreas, which is a helpful way of thinking about it. Basically, it works by linking an insulin pump with a continuous glucose monitor to regulate a person’s insulin with little input needed from the user. In September 2016, the Journal of the American Medical Association (JAMA) reported on a successful trial of a closed-loop insulin delivery system for patients with type 1 diabetes over the age of 14. More recently, we described a study that found that an artificial pancreas system is safe and effective in children as young as six years old who have type 1 diabetes.
Now a new study from researchers in Australia reports that not only did a closed-loop system result in better blood sugar control in young people, but it also improved their quality of life. The study was reported in the journal JAMA Pediatrics, and the quality-of-life issues were the main thrust of the research. As the researchers wrote, although “hybrid closed-loop (HCL) therapy has improved glycemic control in children and adolescents with type 1 diabetes … the efficacy of HCL on glycemic and psychosocial outcomes has not yet been established in a long-term randomized clinical trial.”
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The researchers recruited 135 subjects between the ages of 12 and 25, all of whom had type 1 diabetes for a year or more. The subjects came from five pediatric diabetes centers throughout Australia. The average age of the patients was 15.3, and about eight of ten were under 18. Sixty-eight subjects were randomly assigned to a group that utilized conventional diabetes therapy (either continuous subcutaneous insulin infusion or repeated insulin injections throughout the day, with or without continuous blood sugar monitoring), and 67 subjects were assigned to use a closed-loop system, which in this study was a combination of the MiniMed 670G pump manufactured by Medtronic and a Guardian Link 3 transmitter. The subjects were recruited between April 18, 2017, and October 4, 2019, and the data were analyzed from July 25, 2020, to February 26, 2021.
Closed-loop system improved time in range
The trial lasted six months. The first thing the researchers noted had to do with how much time the subjects spent in what’s known as time in range, or TIR. The target glucose range was from 70 mg/dl to 180 mg/dl. They reported that the participants who used the closed-loop system experienced a jump in TIR from 53.1%at the beginning of the study to a TIR 62.5% at the end. The control group also experienced a rise in TIR, but it was much smaller — from 54.6% to 56.1%. The closed-loop therapy also reduced the time that participants spent in a low blood sugar range. The effect was observed at all times of the day and was even greater at night. As the authors put it, “The recommended [time in range] of greater than 70% was achieved in fewer than 10% of the participants at baseline on conventional therapy, highlighting the complexities of diabetes management in this cohort. With the [closed-loop] system, 31% met this target.”
Closed-loop system also improved time in range
The researchers assessed the psychological status of the study subjects by using a standard measurement tool called the Pediatric Quality of Life Inventory (PedsQL), which is a 23-item health status questionnaire used by both parent and child that evaluates physical functioning, emotional functioning, psychosocial functioning, social functioning, and school functioning in children ages 2 to 18. This research, the study authors reported, found that the closed-loop system “improved diabetes-specific quality of life.”
The subjects tolerated the closed-loop system well, but one slight problem was observed — skin reactions from the sensor. The users were not uncomfortable enough to discontinue the device, but the authors noted that future developments of closed-loop technology will need to take this issue into account.
Want to learn more about continuous glucose monitoring? Read “CGM for Diabetes Management.” Want to learn more about insulin pumps? Read “Ways to Deliver Insulin: Inhalers and Pumps” and “How to Pick an Insulin Pump or CGM.”