The Medtronic MiniMed™ 670G hybrid closed-loop system was designed to automatically adjust basal insulin delivery every 5 minutes based on sensor glucose (SG) values. Its safety and effectiveness have been recently investigated in a multi-center pivotal trial conducted in 1T1D children aged 7-13 years.

During the 2 week run-in phase, participants used the system in Manual Mode. This was followed by a 3-month at-home study phase in which the Auto Mode feature was enabled. The SG data and the amount of insulin delivered were analyzed during the overnight period (11:00 p.m.-7:00 a.m.).

Figure-1 (top panel) shows overnight SG tracings from the run-in phase and study phase, and that the median [IQR] reduced significantly from run-in (142 [71]mg/dL) to study phase (126 [34]mg/dL), by 7:00 a.m. This was mainly achieved by the system transferring variability from SG to insulin infusion rate (bottom panel). During the nighttime period, the system suspended insulin for an average 1.3 hours and delivered insulin at the maximum allowable limit for an average 3.6 hours. The remainder of the time, it delivered insulin between 1-99% of the maximum allowable limit.

These data suggest that greater variability of basal insulin delivery, such as that achieved with MiniMed™ 670G system automation, compared to fixed pre-set basal rates, improves nighttime glucose control in children.


A. Roy: Employee; Self; Medtronic MiniMed, Inc. B. Grosman: Employee; Self; Medtronic. N. Parikh: Employee; Self; Medtronic. D. Wu: None. S.W. Lee: Employee; Self; Medtronic. F.R. Kaufman: Employee; Self; Medtronic.

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