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Closed-loop insulin delivery effective in extended setting
Glucose control was improved and hypoglycemia was reduced in patients with type 1 diabetes who used closed-loop insulin delivery for 12 weeks, according to recent study findings published in The New England Journal of Medicine.
“The artificial beta cell, or closed-loop insulin-delivery system, expands on the concept of sensor-responsive insulin delivery,” the researchers wrote. “The closed-loop system differs from conventional pump therapy and threshold-suspend approaches in that it uses a control algorithm that autonomously and continually increases and decreases the subcutaneous delivery of insulin on the basis of real-time sensor glucose levels.”
Roman Hovorka
Roman Hovorka, PhD, of the Wellcome Trust-Medical Research Council Institute of Metabolic Science at the University of Cambridge, and colleagues evaluated adults (n = 33) and children and adolescents (n = 25) with type 1 diabetes who used a closed-loop insulin-delivery system for a 12-week period (intervention) and sensor-augmented pump therapy (control) for a similar period. The researchers sought to determine the feasibility, improvement in glycemic control and the risk for hypoglycemia of the closed-loop insulin-delivery system without remote monitoring or close supervision.
Among adults, HbA1c levels were in the target range more during the intervention period compared with the control period (P < .001). Compared with the control period, glucose levels were lower (P < .001) and the time spent above the HbA1c target range was lower (P < .001) with the intervention period. The risk for hypoglycemic — measured by area under the curve (AUC) when the glucose level was less than 63 mg/dL — was 39% lower in the intervention period compared with the control period (P < .001).
Among children and adolescents, nighttime glucose level was in the target range more in the intervention period compared with the control period (P < .001). Mean overnight glucose (P < .001) and time spent over the target range (P < .001) also was lower during the intervention period vs. the control period.
“In conclusion, we found that extended use of a closed-loop system at home over a period of 12 weeks during free daily living without close supervision is feasible in adults, children and adolescents with type 1 diabetes,” the researchers wrote. “Improvements in glucose control and reductions in the burden of hypoglycemia were observed. Among adults, the [HbA1c] level was lower with the use of a closed-loop system day and night than with a sensor-augmented insulin pump, even when the insulin pump was adjusted appropriately.” – by Amber Cox
Disclosure: Hovorka reports receiving grants from the Juvenile Diabetes Research Foundation, the Framework Programme 7 European Union Research Programmes, the National Institute for Health Research Cambridge Biomedical Research Centre and the Wellcome Strategic Award; non-financial support from Abbott Diabetes Care and Diasend; personal fees from BBraun, Eli Lilly, Medtronic, Novo Nordisk, Profil and Sanofi Aventis; and has patents related to safety hybrid open-close loop system, a model based closed loop system, an overnight closed-loop insulin delivery with model predictive control and glucose measurement error model and a system for insulin delivery using glucose regulation and measurement error models. Please see the full study for a list of all other authors’ relevant financial disclosures.