Comparing Closed-Loop Systems With Sensor-Augmented Pumps in Pediatric T1D Populations

A 16-week trial involving over 100 children with type 1 diabetes (T1D) found glucose level was in the target range for a greater percentage of time in individuals who used a closed-loop system compared with those who used a sensor-augmented insulin pump.

Results from the study are published in The New England Journal of Medicine. The trial was funded in part by Tandem Diabetes Care.

Less than 20% of children with T1D attain the glycemic target of a glycated hemoglobin (A1C) level of less than 7%, while the use of a closed-loop system automating insulin delivery may improve glycemic outcomes and quality of life in this population, authors wrote.

Closed-loop systems, also known as automated insulin delivery systems or an artificial pancreas, require user engagement to inform the system of the insulin bolus dose at mealtimes.

To determine the efficacy and safety of Tandem Diabetes Care’s t:slim X2 insulin pump with Control-IQ Technology, researchers conducted a randomized trial of 101 children with T1D between ages 6 and 13.

Participants were recruited to the multicenter open-label trial from 4 pediatric diabetes centers across the United States.

“The patients in the closed-loop group [n = 78] were trained in the use of the closed-loop system, which consisted of a t:slim X2 insulin pump with Control-IQ Technology and a continuous glucose monitor (Dexcom G6, Dexcom), which transmitted glucose values to the pump,” researchers explained.

Meanwhile, patients in the control group (n = 23) used Dexcom G6 sensors, and those who had been using an insulin pump prior to the trial continued to use their personal pumps. Individuals who had been receiving injections were provided with a t:slim X2 pump.

The percentage of time the glucose level was in the target range of 70 to 180 mg per deciliter (3.9 to 10.0 mmol per liter) was the primary outcome of the study.

Before the trial, 81 patients used insulin pumps, 20 received multiple daily injections, and 93 patients used a continuous glucose monitor. In addition, “during the trial, 15 of the 23 patients in the control group used the t:slim X2 pump with a predictive low-glucose suspend feature.” Baseline A1C levels ranged from 5.7% to 10.1%.

Of the 100 patients who completed the trial, analyses revealed:

• Mean (SD) percentage of time glucose level was in the target range increased from 53 (17%) at baseline to 67 (10%) (mean over 16 weeks of treatment) in the closed-loop group and from 51 (16%) to 55 (13%) in the control group (mean adjusted difference, 11 percentage points [equivalent to 2.6 hours per day]; 95% CI, 7-14; P < .001)
• In both groups, median percentage of time glucose level was below 70 mg per deciliter was low (1.6% in the closed-loop group and 1.8% in the control group)
• In the closed-loop group, median percentage of time the system was in the closed-loop mode was 93% (interquartile range, 91-95)
• Mean percentage of time that the glucose level was in the target range during the daytime (6 am to midnight) was 63% in the closed-loop group and 56% in the control group, and the corresponding values during the nighttime (midnight to 6 am) were 80% and 54%
• The glycemic target of an A1C of less than 7% was met in 39 patients (51%) in the closed-loop group and in 4 patients (18%) in the control group at 16 weeks

Although no episodes of diabetic ketoacidosis or severe hypoglycemia occurred in either group, a total of 16 adverse events (AEs) were reported in 15 patients in the closed-loop group and 3 AEs in 2 patients in the control group. Authors noted most AEs were associated with hyperglycemia and ketonemia cause by pump infusion set failure.

Because the study population did not include diverse participants with regard to socioeconomic status, A1C levels, and the use of devices for diabetes management, results may not be generalizable.

“Further studies will be needed to explore whether the effectiveness of the closed-loop system shown in the current trial would be similar in groups with lower socioeconomic status and less familiarity with technology,” researchers wrote.

The amount of hypoglycemia at baseline was also low in both groups, limiting the ability of the trial to assess the impact of the closed-loop system on the condition.

Reference

Breton MD, Kanapka LG, Beck RW, et al. A randomized trial of closed-loop control in children with type 1 diabetes. N Eng J Med. Published online August 26, 2020. doi:10.1056/NEJMoa2004736