Advanced Hybrid Closed Loop System Could Improve Glucose Control in Youth with High-Risk Type 1 Diabetes

Benjamin Wheeler, MBChB, PhD

Results of a new study have investigators purporting advanced hybrid closed loop therapy should be considered a first-line option for youth with high-risk type 1 diabetes using multiple daily injections.

A single-arm, dual-center study of people with high-risk type 1 diabetes aged 13-25 with an HbA1c of 8.5% or greater, results of the study demonstrate use of advanced hybrid closed loop therapy in the patient population was associated with a nearly 3 percentage point reduction in HbA1c at 3 months, with a gain of more than 30 percentage points for time spent in target range.

“This study describes the greatest gains so far reported for youth with high-risk glycemia, with a mean HbA1c improvement of 2.9 percentage points (31.5 mmol/mol). Mean TIR improved by 38.9 percentage points, mostly accounted for by a reduction of 38.4 percentage points in time spent above 250 mg/dL,” wrote investigators.

As diabetes technologies have advanced, so too has the range of patients leveraging these advances. At the forefront of diabetes technologies are continuous glucose monitoring and insulin pump systems. Although advanced hybrid closed loop systems have been examined in youth with type 1 diabetes, investigators pointed out previous studies have focused on patients aged 7-17 years and also excluded those with an HbA1c exceeding 12.4%. Led by Benjamin Wheeler, MBChB, PhD, an associate professor and pediatric endocrinologist at the University of Otago, and a team of collaborators launched the current study, which was funded by a Lottery Research Grant, with the intent of exploring utility of an advanced hybrid close loop system in those with type 1 diabetes aged 13-25 years, without an upper cutoff for HbA1c to enter.

The primary outcomes of interest for the study were the time in range of 70-180 mg/dL and change in HbA1c between baseline and the end of the study period. In the study, the advanced hybrid closed loop system consisted of the Medtronic MiniMed 780G insulin pump and the Guardian Sensor 3 with Guardian Link 3 transmitter. Investigators adapted a 10-day initiation protocol for the study, with a key adaption being a structured 72-hour rapid onboarding.

Overall, 20 participants underwent enrollment between October 6, 2021-February 1, 2022 and completed the 3-month intervention. This cohort had a mean age of 18.8 (13.3-25.7), 60% were female, mean HbA1c of 10.5% (SD, 2.1), mean BMI of 25.2 (SD, 5.9) kg/m2, mean duration of diabetes of 9.7 (SD, 5.4) years, and a mean total daily dose of insulin was 71.1 (SD, 25.7) units.

Upon analysis, results indicated the mean HbA1c among the cohort decreased from 10.5% (SD, 2.1) at baseline to 7.6% (SD, 1.1) at 3 months (difference, 2.9 percentage points). Additionally, the time spent in target range of 70-180 mg/dL increased from 27.6% (SD, 13.2) at baseline to 66.5 (SD, 9.8) at 3 months (difference, 38.9 percentage points), with this improvement in time in range driven by a 38.4 percentage point reduction in time spent above 250 mg/dL. In their conclusion, investigators called attention to a participant within the study with a baseline HbA1c of 17.6% and 0% time in target range, who reduced HbA1c to 7.9% and improved time in target range to 60% at 3 months.

“For less complex type 1 diabetes populations, closed loop systems are already the gold standard therapeutic option. AHCL, combined with adequate training and clinical support, should now be considered a first-line therapeutic tool for those with the most to gain, namely youth with high-risk glycemia,” investigators concluded.

This study, “Impact of Advanced Hybrid Closed Loop on Youth With High-Risk Type 1 Diabetes Using Multiple Daily Injections,” was published in Diabetes Care.