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Diabetes Care. 2014 Jul;37(7):1789-96. doi: 10.2337/dc13-2076. Epub 2014 Jun 14.

Safety of outpatient closed-loop control: first randomized crossover trials of a wearable artificial pancreas.

Author information

1
Center for Diabetes Technology and Department of Medicine, Division of Endocrinology, University of Virginia, Charlottesville, VA boris@virginia.edu.
2
Department of Endocrinology, Diabetes, and Nutrition, Montpellier University Hospital, INSERM Clinical Investigation Center 1001, Institute of Functional Genomics, CNRS UMR 5203, INSERM U661, University of Montpellier 1, Montpellier, France.
3
Department of Information Engineering and Department of Internal Medicine, Unit of Metabolic Disease, University of Padova, Padova, Italy.
4
Sansum Diabetes Research Institute, Santa Barbara, CA.
5
Center for Diabetes Technology and Department of Medicine, Division of Endocrinology, University of Virginia, Charlottesville, VA.
6
Department of Systems Engineering, University of Pavia, Pavia, Italy.
7
Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA.

Abstract

OBJECTIVE:

We estimate the effect size of hypoglycemia risk reduction on closed-loop control (CLC) versus open-loop (OL) sensor-augmented insulin pump therapy in supervised outpatient setting.

RESEARCH DESIGN AND METHODS:

Twenty patients with type 1 diabetes initiated the study at the Universities of Virginia, Padova, and Montpellier and Sansum Diabetes Research Institute; 18 completed the entire protocol. Each patient participated in two 40-h outpatient sessions, CLC versus OL, in randomized order. Sensor (Dexcom G4) and insulin pump (Tandem t:slim) were connected to Diabetes Assistant (DiAs)-a smartphone artificial pancreas platform. The patient operated the system through the DiAs user interface during both CLC and OL; study personnel supervised on site and monitored DiAs remotely. There were no dietary restrictions; 45-min walks in town and restaurant dinners were included in both CLC and OL; alcohol was permitted.

RESULTS:

The primary outcome-reduction in risk for hypoglycemia as measured by the low blood glucose (BG) index (LGBI)-resulted in an effect size of 0.64, P = 0.003, with a twofold reduction of hypoglycemia requiring carbohydrate treatment: 1.2 vs. 2.4 episodes/session on CLC versus OL (P = 0.02). This was accompanied by a slight decrease in percentage of time in the target range of 3.9-10 mmol/L (66.1 vs. 70.7%) and increase in mean BG (8.9 vs. 8.4 mmol/L; P = 0.04) on CLC versus OL.

CONCLUSIONS:

CLC running on a smartphone (DiAs) in outpatient conditions reduced hypoglycemia and hypoglycemia treatments when compared with sensor-augmented pump therapy. This was accompanied by marginal increase in average glycemia resulting from a possible overemphasis on hypoglycemia safety.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT01714505 NCT01727817 NCT01742741.

PMID:
24929429
PMCID:
PMC4067397
DOI:
10.2337/dc13-2076
[Indexed for MEDLINE]
Free PMC Article

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