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      Closed-Loop Control Without Meal Announcement in Type 1 Diabetes

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          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.

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          Author and article information

          Diabetes Technol Ther
          Diabetes Technol. Ther
          Diabetes Technology & Therapeutics
          Mary Ann Liebert, Inc. (140 Huguenot Street, 3rd FloorNew Rochelle, NY 10801USA )
          01 September 2017
          01 September 2017
          01 August 2018
          : 19
          : 9
          : 527-532
          [ 1 ]Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute , Troy, New York.
          [ 2 ]Department of Pediatric Endocrinology, Stanford University , Stanford, California.
          [ 3 ]Department of Pediatrics, Barbara Davis Center for Childhood Diabetes , Aurora, Colorado.
          [ 4 ]Division of Endocrinology, Icahn School of Medicine at Mount Sinai , New York, New York.
          [ 5 ]Department of Systems and Information Engineering, University of Virginia , Charlottesville, Virginia.
          Author notes
          Address correspondence to: Faye M. Cameron, PhD, 3808` Northbrook Drive, Boulder, CO 80304, E-mail: fmccamer@ 123456gmail.com
          PMC5647490 PMC5647490 5647490 10.1089/dia.2017.0078
          Copyright 2017, Mary Ann Liebert, Inc.
          Page count
          Figures: 3, Tables: 1, References: 19, Pages: 6
          Original Articles


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