title: Evaluating the Performance of a Novel Embedded Closed-loop System.
abstract: The objective was to assess the reliability of a novel automated closed-loop glucose control system developed within the AP@home consortium in adults with type 1 diabetes. Eight adults with type 1 diabetes on insulin pump therapy (3 men; ages 40.5 ± 14.3 years; HbA1c 8.2 ± 0.8%) participated in an open-label, single-center, single-arm, 12-hour overnight study performed at the clinical research facility. A standardized evening meal (80 g CHO) accompanied by prandial insulin boluses were given at 19:00 followed by an optional snack of 15 g at 22:00 without insulin bolus. Automated closed-loop glucose control was started at 19:00 and continued until 07:00 the next day. Basal insulin delivery (Accu-Chek Spirit, Roche) was automatically adjusted by Cambridge model predictive control algorithm, running on a purpose-built embedded device, based on real-time continuous glucose monitor readings (Dexcom G4 Platinum). Closed-loop system was operational as intended over 99% of the time. Overnight plasma glucose levels (22:00 to 07:00) were within the target range (3.9 to 8.0 mmol/l) for 75.4% (37.5, 92.9) of the time without any time spent in hypoglycemia (<3.9 mmol/l). Mean overnight glucose was 7.8 ± 1.3 mmol/l. For the entire 12-hour closed-loop period (19:00 until 07:00) plasma glucose levels were within the target range (3.9 to 10.0 mmol/l) for 84.4% (63.3, 100) of time. There were no adverse events noted during the trial. We observed a high degree of reliability of the automated closed-loop system. The time spent in target glucose level overnight was comparable to results of previously published studies. Further developments to miniaturize the system for home studies are warranted.
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
authors.forename: Lalantha
authors.initials: L
authors.lastname: Leelarathna
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
authors.forename: Hood
authors.initials: H
authors.lastname: Thabit
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
authors.forename: Janet M
authors.initials: JM
authors.lastname: Allen
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
authors.forename: Marianna
authors.initials: M
authors.lastname: Nodale
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK Department of Paediatrics, University of Cambridge, Cambridge, UK.
authors.forename: Malgorzata E
authors.initials: ME
authors.lastname: Wilinska
authors.affiliation: Triteq Ltd, Station Road, Hungerford, Berkshire, UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Powell
authors.affiliation: Triteq Ltd, Station Road, Hungerford, Berkshire, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Lane
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Evans
authors.affiliation: Wellcome Trust-MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK Department of Paediatrics, University of Cambridge, Cambridge, UK rh347@cam.ac.uk.
authors.forename: Roman
authors.initials: R
authors.lastname: Hovorka
keywords: AP@home consortium; Dexcom G4 Platinum; MPC algorithm; closed-loop; continuous glucose monitoring