medwireNews: The first major home use trial to include children younger than 13 years shows that an artificial pancreas system improves overnight glucose control.

After initial training and run-in use, the 25 children, who were aged between 6 and 18 years (average 12 years), were not monitored or supervised by the study investigators and were free to undertake their usual daily activities.

The children activated the system after dinner or at bedtime and switched it off before breakfast the next day. During 12 weeks of nightly use of the closed-loop system, the children’s overnight glucose levels remained in range (70–145 mg/dL) for 59.7% of the time, on average, compared with 34.4% of the time during a control 12-week period when they used a sensor-augmented insulin pump.

The order of the treatment and control periods was randomly assigned, with a 3- to 4-week washout period between them.

Closed-loop delivery resulted in a significant reduction in the amount of time children’s overnight glucose levels were above 145 mg/dL, at 37.2% versus 60.7% in the control period, and did not increase the amount of time their levels were below 70 or 50 mg/dL. The night-to-night variability in glucose levels was also significantly reduced.

“Extended benefits from overnight use of the closed-loop system in children and adolescents were seen over the full 24-hour period”, write Roman Hovorka (University of Cambridge, UK) and study co-authors in The New England Journal of Medicine.

Over the full 24 hours, children had a significant reduction in time with glucose levels outside the target range (70–180 mg/dL), and had a significant 42% reduction in hypoglycaemia burden (time at <63 mg/dL).

Furthermore, the time spent in hypoglycaemia was significantly reduced during the daytime period, when they were not using the closed-loop system, and there was a tendency to less time with levels below 50 mg/dL, particularly between breakfast and midday, when there was a significant 79% reduction compared with in the control period.

The team also conducted a separate randomised trial in 33 adults, who used the closed-loop system both at night and during the day for 12 weeks, with supplementary bolus insulin injections before eating. Again, this resulted in a significant 11% increase in the time spent within target glucose range relative to in the control period, as well as reduced glucose variability and a reduction in hypoglycaemic burden.

Adults also achieved a significant reduction in glycated haemoglobin during the closed-loop relative to the control period, at 7.3% versus 7.6%; children had a nonsignificant difference of 7.6% versus 7.9%.

By Eleanor McDermid, Senior medwireNews Reporter

N Engl J Med 2015; Advance online publication

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