In a small study of 10 type 1 children under the age of seven years, closed-loop insulin delivery improved their nighttime glycemic control. The therapy, delivered at Children’s Hospital Boston, used an algorithm-controlled pump and continuous glucose monitor to deliver insulin on an as-needed basis as the children slept.
During the overnight period, which extended from 10 p.m. to 8 a.m, the delivery device adjusted basal rates every 20 minutes based on feedback from the sensors. In the morning, from 8 a.m. to noon, mini-boluses were given once a minute based on sensor readings. Target blood sugars were 150 mg/dL for the time from 10 p.m. until 6 a.m., and 120 mg/dL from 6 a.m. until noon.
Although the researchers found that the closed-loop device allowed the children to stay longer in the target glucose range overnight (5.3 hours, versus 3.2 hours without the system), they said that the difference was not statistically significant. However, they did find a substantial improvement in the time spent with blood glucose levels above 300 mg/dL: about 11 minutes with the device, versus 78 minutes without it. Noon readings were 189 mg/dL using the closed-loop system, versus 273 mg/dL without it.
According to head researcher Dr. Andrew Dauber, the findings demonstrate that closed-loop therapy decreases nighttime hyperglycemia in young children without increasing the risk of hypoglycemia. He said the study of what he called an underrepresented group will figure into the eventual development of the long-awaited artificial pancreas.