American Diabetes Association
REVISED_Supplemental_material_6-21-2021.pdf (536.23 kB)

Advanced Closed-Loop Control System Improves Postprandial Glycemic Control Compared With a Hybrid Closed-Loop System Following Unannounced Meal

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Version 2 2021-08-16, 10:48
Version 1 2021-08-15, 18:49
posted on 2021-08-16, 10:48 authored by Jose Garcia-Tirado, Jenny L. Diaz, Rebeca Esquivel-Zuniga, Chaitanya L. K. Koravi, John P. Corbett, Martha Dawson, Christian Wakeman, Charlotte L. Barnett, Mary C. Oliveri, Helen Myers, Katie Krauthause, Marc D. Breton, Mark D. DeBoer
Objective: Meals are a major hurdle to glycemic control in type 1 diabetes (T1D). Our objective was to test a fully-automated closed-loop control (CLC) system in the absence of announcement of carbohydrate ingestion among adolescents with T1D, who are known to commonly omit meal announcement.

Research Design and Methods: Eighteen adolescents with T1D (age 15.6±1.7 years; HbA1c 7.4%±1.5; 9F/9M) participated in a randomized crossover clinical trial comparing our legacy hybrid CLC system (USS-Virginia) with a novel fully-automated CLC system (RocketAP), during two 46h supervised admissions (each with one announced and one unannounced dinner), following 2 weeks of data collection. Primary outcome was the percent time-in-range 70-180mg/dL (TIR) following the unannounced meal, with secondary outcomes related to additional CGM-based metrics.

Results: Both TIR and time-in-tight-range 70-140mg/dL (TTR) were significantly higher using RocketAP than using USS-Virginia during the 6h following the unannounced meal (83% [64-93] vs. 53% [40-71]; p=0.004 and 49% [41-59] vs. 27% [22-36]; p=0.002, respectively), primarily driven by reduced time-above-range (TAR >180mg/dL 17% [1.3-34] vs. 47% [28-60]), with no increase in time-below-range (TBR <70mg/dL 0% median for both). RocketAP also improved control following the announced meal (mean difference TBR: -0.7%, TIR: +7%, TTR: +6%), overall (TIR: +5%, TAR: -5%, TTR: +8%), and overnight (TIR: +7%, TTR: +19%, TAR: -5%). RocketAP delivered less insulin overall (78±23U vs. 85±20U, p=0.01)

Conclusions: A new fully-automated CLC system with automatic prandial dosing was proven to be safe and feasible and outperformed our legacy USS-Virginia in an adolescent population with and without meal announcement.


The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This project was funded by generous grants from the University of Virginia’s LaunchPad Program (to MDD and MDB) and the Strategic Investment Fund project “Precision Individualized Medicine for Diabetes (PriMeD).”


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