medwireNews: Patients with type 1 diabetes who move to a DIY closed-loop insulin delivery system have significant improvements in their glycemic control, shows an analysis of continuous glucose monitoring (CGM) data.
Dana Lewis (OpenAPS, Seattle, Washington, USA) noted that these patients represent “a highly motivated population,” with good glycemic control at baseline, yet by closing the loop they achieved marked improvements in the time they spent in the blood glucose range of 70 to 180 mg/dL, from 75.8% to 82.2%.
Lewis and team analyzed CGM data from 20 patients with type 1 diabetes 4–6 weeks before and after they moved to a DIY closed-loop system. The patients were aged an average of 30.2 years and had used an insulin pump for an average of 15.7 years and CGM for 4.7 years.
All except two patients showed improvements during this time, which Lewis said she was “pleasantly surprised” to see, explaining that individual patients choose their own blood glucose target when initiating closed-loop control, and the OpenAPS community advises using a conservative target initially, while the user gets used to the system.
The improvement was mostly down to a reduction in the time spent with blood glucose above 180 mg/dL, which fell from 18.3% to 13.3%. Time spent above 250 and 300 mg/dL fell from 5.0% to 2.5% and from 1.7% to 0.35%, respectively.
Patients’ average blood glucose levels fell from 135.7 to 128.3 mg/dL and their glycated hemoglobin declined from 6.4% to 6.1%, Lewis told attendees at the ADA’s 78th Scientific Sessions in Orlando, Florida, USA.
There was a nonsignificant reduction in the time spent with blood glucose below 70 mg/dL, from 6.0% to 4.5%, and a significant reduction in time below 50 mg/dL, from 1.9% to 1.1%.
Lewis noted that the largest improvements were seen during the day, despite the researchers expecting the greatest benefits to occur for overnight glycemic control, which she attributed to the system providing support while patients cope with mealtimes, exercise, and other challenges. Time in range improved from 73.8% to 80.2% in the daytime and from 80.4% to 86.2% at night.
Some patients had been using DIY closed-loop insulin delivery for a year or more by the time of data collection, and these patients maintained their improved glycemic control over that time, Lewis added.
She recommended that future studies also look at life quality measures, including time spent managing diabetes.
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