Real-Time Hypoglycemia Prediction Suite Using Continuous Glucose Monitoring

A safety net for the artificial pancreas

  1. Francis J. Doyle III, PHD1,2
  1. 1Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California;
  2. 2Sansum Diabetes Research Institute, Santa Barbara, California;
  3. 3Department of Aeronautics and Astronautics, Stanford University, Palo Alto, California;
  4. 4Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York;
  5. 5Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Aurora, Colorado;
  6. 6Department of Pediatrics, Division of Pediatric Endocrinology, Stanford Medical Center, Palo Alto, California.
  1. Corresponding author: Eyal Dassau, dassau{at}engineering.ucsb.edu.

Abstract

OBJECTIVE The purpose of this study was to develop an advanced algorithm that detects pending hypoglycemia and then suspends basal insulin delivery. This approach can provide a solution to the problem of nocturnal hypoglycemia, a major concern of patients with diabetes.

RESEARCH DESIGN AND METHODS This real-time hypoglycemia prediction algorithm (HPA) combines five individual algorithms, all based on continuous glucose monitoring 1-min data. A predictive alarm is issued by a voting algorithm when a hypoglycemic event is predicted to occur in the next 35 min. The HPA system was developed using data derived from 21 Navigator studies that assessed Navigator function over 24 h in children with type 1 diabetes. We confirmed the function of the HPA using a separate dataset from 22 admissions of type 1 diabetic subjects. During these admissions, hypoglycemia was induced by gradual increases in the basal insulin infusion rate up to 180% from the subject's own baseline infusion rate.

RESULTS Using a prediction horizon of 35 min, a glucose threshold of 80 mg/dl, and a voting threshold of three of five algorithms to predict hypoglycemia (defined as a FreeStyle plasma glucose readings <60 mg/dl), the HPA predicted 91% of the hypoglycemic events. When four of five algorithms were required to be positive, then 82% of the events were predicted.

CONCLUSIONS The HPA will enable automated insulin-pump suspension in response to a pending event that has been detected prior to severe immediate complications.

Footnotes

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • Received August 10, 2009.
  • Accepted January 18, 2010.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.

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