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Clinical Trial
. 2017 Sep;19(9):527-532.
doi: 10.1089/dia.2017.0078. Epub 2017 Aug 2.

Closed-Loop Control Without Meal Announcement in Type 1 Diabetes

Faye M Cameron  1 , Trang T Ly  2 , Bruce A Buckingham  2 , David M Maahs  2   3 , Gregory P Forlenza  3 , Carol J Levy  4 , David Lam  4 , Paula Clinton  2 , Laurel H Messer  3 , Emily Westfall  3 , Camilla Levister  4 , Yan Yan Xie  4 , Nihat Baysal  1 , Daniel Howsmon  1 , Stephen D Patek  5 , B Wayne Bequette  1
Affiliations
Clinical Trial

Closed-Loop Control Without Meal Announcement in Type 1 Diabetes

Faye M Cameron et al. Diabetes Technol Ther. 2017 Sep.

Abstract

Objective: A fully closed-loop insulin-only system was developed to provide glucose control in patients with type 1 diabetes without requiring announcement of meals or activity. Our goal was to assess initial safety and efficacy of this system.

Research design and methods: The multiple model probabilistic controller (MMPPC) anticipates meals when the patient is awake. The controller used the subject's basal rates and total daily insulin dose for initialization. The system was tested at two sites on 10 patients in a 30-h inpatient study, followed by 15 subjects at three sites in a 54-h supervised hotel study, where the controller was challenged by exercise and unannounced meals. The system was implemented on the UVA DiAs system using a Roche Spirit Combo Insulin Pump and a Dexcom G4 Continuous Glucose Monitor.

Results: The mean overall (24-h basis) and nighttime (11 PM-7 AM) continuous glucose monitoring (CGM) values were 142 and 125 mg/dL during the inpatient study. The hotel study used a different daytime tuning and manual announcement, instead of automatic detection, of sleep and wake periods. This resulted in mean overall (24-h basis) and nighttime CGM values of 152 and 139 mg/dL for the hotel study and there was also a reduction in hypoglycemia events from 1.6 to 0.91 events/patient/day.

Conclusions: The MMPPC system achieved a mean glucose that would be particularly helpful for people with an elevated A1c as a result of frequent missed meal boluses. Current full closed loop has a higher risk for hypoglycemia when compared with algorithms using meal announcement.

Keywords: Artificial pancreas; Closed-loop systems; Continuous glucose monitoring.; Postprandial blood glucose.

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Conflict of interest statement

D.M.M. is on the Scientific Advisory board for Insulet, consulting for Abbott, and has benefited from research support to his institution from Medtronic and G.P.F. is a paid consultant for Abbott Diabetes Care. C.J.L. is a paid consultant for NovoNordisk and has had research support from NovoNordisk, Lexicon, and Roche. B.W.B. has consulted for BD. B.A.B. is on Medical Advisory Boards for NovoNordisk, Sanofi, and Convatec and has received research support from Medtronic, Roche, Tandem, and Dexcom.

Figures

<b>FIG. 1.</b>
FIG. 1.
Hotel closed-loop performance for an example subject. Top: Glucose, CGM (black), Reference values (circles). Second: Insulin delivered. Third: Carbs, intervention (squares) and meals (triangles).
<b>FIG. 2.</b>
FIG. 2.
Postprandial control in the inpatient and hotel phase of the trial. Each curve draws from meals that are more than 25 g CHO and patients do not have another meal greater than 25 g CHO within the next 4 h. Twenty-one of 45 inpatient meals and 63 of 100 hotel meals met this criterion.
<b>FIG. 3.</b>
FIG. 3.
Median sensor glucose and interquartile ranges (dotted lines) for 15 hotel subjects during closed-loop and open-loop phases.
See this image and copyright information in PMC

References

    1. Dauber A, Corcia L, Safer J, et al. : Closed-loop insulin therapy improves glycemic control in children aged <7 years. Diabetes Care 2013;36:222–227 - PMC - PubMed
    1. Cameron F, Niemeyer G, Wilson DM, et al. : Inpatient trial of an artificial pancreas based on multiple model probabilistic predictive control with repeated large unannounced meals. Diabetes Technol Ther 2014;16:728–734 - PMC - PubMed
    1. Nimri R, Muller I, Atlas E, et al. : Night glucose control with MD-Logic artificial pancreas in home setting: a single blind, randomized crossover trial-interim analysis. Pediatr Diabetes 2014;15:91–99 - PubMed
    1. Steil GM: Algorithms for a closed-loop artificial pancreas: the case for proportional-integral-derivative control. J Diabetes Sci Technol 2013;7:1621–1631 - PMC - PubMed
    1. Bequette BW: Algorithms for a closed-loop artificial pancreas: the case for model predictive control. J Diabetes Sci Technol 2013;7:1632–1643 - PMC - PubMed

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