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

Abstract

<b>Objective:</b> 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. <p><b>Research Design and Methods: </b>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.</p> <p><b>Results: </b> 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)</p> <p><b>Conclusions:</b> 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.</p>

Carbohydrate Tolerance Threshold for Unannounced Snacks in Children and Adolescents With Type 1 Diabetes Using an Advanced Hybrid Closed-Loop System

“…There is hope that fully closed-loop systems will reduce user burden through a completely automated insulin (or multihormone) delivery; however, the attempts made so far resulted in suboptimal glycemic control because of higher peaks in postprandial glucose or increased time spent in hypoglycemia ( 11 – 13 ). Meanwhile, understanding the potential of currently marketed systems can help improve glycemic control and quality of life for individuals with type 1 diabetes ( 14 ).…”

Automated Insulin Delivery with SGLT2i Combination Therapy in Type 1 Diabetes

“…New algorithms, attempting to predict meal timing, show promise, but have been only tested in small pilot or in silico studies. 17 Combination therapies use drugs that lower glucose levels or/and slow the appearance of meal carbohydrates in the bloodstream. Agents recently tested with AID include the glucagon-like peptide-1 receptor agonist (GLP-1 RA) liraglutide, 18 exenatide, 19 the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin, 20 and the amylin analog pramlintide.…”