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Home Use of Day-and-Night Hybrid Closed-Loop Insulin Delivery in Suboptimally Controlled Adolescents With Type 1 Diabetes: A 3-Week, Free-Living, Randomized Crossover Trial.

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Allen, Janet M 
Wilinska, Malgorzata E 
Thabit, Hood 
Acerini, Carlo L 


OBJECTIVE: This study evaluated the feasibility, safety, and efficacy of day-and-night hybrid closed-loop insulin delivery in adolescents with type 1 diabetes under free-living conditions. RESEARCH DESIGN AND METHODS: In an open-label randomized crossover study, 12 suboptimally controlled adolescents on insulin pump therapy (mean ± SD age 14.6 ± 3.1 years; HbA1c 69 ± 8 mmol/mol [8.5 ± 0.7%]; duration of diabetes 7.8 ± 3.5 years) underwent two 21-day periods in which hybrid closed-loop insulin delivery was compared with sensor-augmented insulin pump therapy in random order. During the closed-loop intervention, a model predictive algorithm automatically directed insulin delivery between meals and overnight. Participants used a bolus calculator to administer prandial boluses. RESULTS: The proportion of time that sensor glucose was in the target range (3.9-10 mmol/L; primary end point) was increased during the closed-loop intervention compared with sensor-augmented insulin pump therapy by 18.8 ± 9.8 percentage points (mean ± SD; P < 0.001), the mean sensor glucose level was reduced by 1.8 ± 1.3 mmol/L (P = 0.001), and the time spent above target was reduced by 19.3 ± 11.3 percentage points (P < 0.001). The time spent with sensor glucose levels below 3.9 mmol/L was low and comparable between interventions (median difference 0.4 [interquartile range -2.2 to 1.3] percentage points; P = 0.33). Improved glucose control during closed-loop was associated with increased variability of basal insulin delivery (P < 0.001) and an increase in the total daily insulin dose (53.5 [39.5-72.1] vs. 51.5 [37.6-64.3] units/day; P = 0.006). Participants expressed positive attitudes and experience with the closed-loop system. CONCLUSIONS: Free-living home use of day-and-night closed-loop in suboptimally controlled adolescents with type 1 diabetes is safe, feasible, and improves glucose control without increasing the risk of hypoglycemia. Larger and longer studies are warranted.



Adolescent, Blood Glucose, C-Peptide, Child, Cross-Over Studies, Diabetes Mellitus, Type 1, Female, Glycated Hemoglobin, Humans, Insulin, Male, Surveys and Questionnaires, Time Factors, Treatment Outcome, Urinalysis

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Diabetes Care

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American Diabetes Association
Cambridge University Hospitals NHS Foundation Trust (CUH) (Roman Hovorka)
National Institute of Diabetes and Digestive and Kidney Diseases (R01DK085621)
National Institute of Diabetes and Digestive and Kidney Diseases (Grant ID: 1R01DK085621-01), JDRF, National Institute for Health Research Cambridge Biomedical Research Centre, Wellcome Trust (Strategic Award: 100574/Z/12/Z)