Overnight use of artificial pancreas improves 24-hour glycemic control
BOSTON — Resetting blood glucose levels to near normal range after overnight use of a closed-loop artificial pancreas system more effectively controls subsequent daytime blood glucose levels in adults with type 1 diabetes than the use of conventional insulin pump therapy, according to study findings presented here.
In a randomized, crossover, multicenter study comparing overnight closed-loop control in outpatient and home settings with the use of an insulin pump, researchers found the artificial pancreas system resulted in increased time spent in the target glucose range, as well as reduced hypoglycemia, during the night and overall.
“Our intent was to investigate whether overnight-only closed loop can improve 24-hour glycemic control,” Sue A. Brown, MD, an assistant professor in the department of medicine at the University of Virginia, said while presenting the findings at the American Diabetes Association’s 75th Scientific Sessions.
Sue A. Brown
The system is designed to aim for tight glycemic control every morning and “reset” the patient to normoglycemia before wake-up, she said.
Brown and colleagues from the University of Virginia, Mount Sinai Hospital, Mayo Clinic and the University of Padova in Italy analyzed data from 36 adults with type 1 diabetes on traditional insulin pump therapy from age 21 to 65 years and an HbA1c level of less than 10% (mean age, 46 years; mean HbA1c, 7.4%; mean duration of diabetes, 29 years). Participants (29 women) were randomly assigned to an artificial pancreas from 11 p.m. until 7 a.m. for 5 nights, followed by 5 nights of conventional insulin pump therapy. The artificial pancreas system included Diabetes Assistant (DiAs; a smartphone platform), DexCom G4 Platinum and Roche Accu-Chek Combo. Researchers instructed participants to mimic usual activities during both control and experimental sessions; food was unrestricted during the day, including restaurant meals.
In an at-home substudy conducted at the University of Virginia and University of Padova, 10 participants (five at each site; mean age, 45 years; mean HbA1c, 7%) completed 5 nights with insulin pump therapy in an outpatient setting, followed by 5 nights of closed-loop control at home.
“This was the first time the system was taken home in the U.S.,” Brown said. “So this served as a pilot [program] for feasibility at home.”
During overnight closed-loop insulin delivery, 78.3% of participants had blood glucose levels in the target range (70-180 mg/dL) during a 24-hour period vs. 71.5% on insulin pump therapy (P = .003). Closed-loop delivery in the home and outpatient settings also significantly reduced the time spent hypoglycemic compared with insulin pump therapy, Brown said (< 70 mg/dL, 1.3% in the home setting; 1.2% in the outpatient setting; 3.9% for insulin pump therapy; P = .016).
Mean glucose at 7 a.m. (home, 121.2 ± 3.2 mg/dL; outpatient, 119.4 ± 7.1 mg/dL; insulin pump, 134.1 ± 15.4 mg/dL), mean glucose overnight (home, 141.6 ± 9.9 mg/dL; outpatient, 134.5 ± 6.1 mg/dL; insulin pump, 153.9 ± 21 mg/dL) and time spent in the target glucose range of 70 mg/dL to 180 mg/dL (home, 82.7%; outpatient, 89.7%; insulin pump, 68.6%) improved as well, and home and outpatient control were similar.
Overnight control correlated with following daytime control (P = .01), according to researchers.
“Compared to [insulin pump therapy], both closed-loop control conditions resulted in significant improvement in hypoglycemia and glycemic control, with the potential to improve daytime control when glucose levels are ‘reset’ to normoglycemia each morning,” the researchers wrote. – by Regina Schaffer
Brown SA, et al. Abstract 224-OR. Presented at: American Diabetes Association’s 75th Scientific Sessions; June 5-9, 2015; Boston.
Disclosure: Brown reports various financial ties with Animas Corp., Dexcom Inc., Medtronic and Roche Diagnostics.