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Diabetes Care. 2016 May;39(5):830-2. doi: 10.2337/dc15-2623. Epub 2016 Mar 10.

Variability of Insulin Requirements Over 12 Weeks of Closed-Loop Insulin Delivery in Adults With Type 1 Diabetes.

Author information

1
Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K. Department of Paediatrics, University of Cambridge, Cambridge, U.K.
2
Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K. Department of Diabetes and Endocrinology, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, U.K.
3
Department of Diabetes and Endocrinology, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, U.K.
4
Profil, Neuss, Germany.
5
Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
6
Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, U.K. Department of Paediatrics, University of Cambridge, Cambridge, U.K. rh347@cam.ac.uk.

Abstract

OBJECTIVE:

To quantify variability of insulin requirements during closed-loop insulin delivery.

RESEARCH DESIGN AND METHODS:

We retrospectively analyzed overnight, daytime, and total daily insulin amounts delivered during a multicenter closed-loop trial involving 32 adults with type 1 diabetes. Participants applied hybrid day-and-night closed-loop insulin delivery under free-living home conditions over 12 weeks. The coefficient of variation was adopted to measure variability of insulin requirements in individual subjects.

RESULTS:

Data were analyzed from 1,918 nights, 1,883 daytime periods and 1,564 total days characterized by closed-loop use over 85% of time. Variability of overnight insulin requirements (mean [SD] coefficient of variation 31% [4]) was nearly twice as high as variability of total daily requirements (17% [3], P < 0.001) and was also higher than variability of daytime insulin requirements (22% [4], P < 0.001).

CONCLUSIONS:

Overnight insulin requirements were significantly more variable than daytime and total daily amounts. This may explain why some people with type 1 diabetes report frustrating variability in morning glycemia.

PMID:
26965717
DOI:
10.2337/dc15-2623
[Indexed for MEDLINE]

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