Clinical Assessment of a Closed-loop System With Glucagon, Exercise and Mixed Meals

Detailed Summary

The diabetes technology group at Imperial College have developed a bio-inspired artificial pancreas (BiAP) system which uses a control algorithm based on a mathematical model of beta-cell physiology. The algorithm is implemented on a miniature silicon microchip within a portable handheld device, which interfaces the components of the artificial pancreas. Development of closed-loop insulin delivery devices to intensify control without hypoglycaemia has been extensively reviewed and have shown encouraging results . However, they have not yet proven to be robust when challenged with uncertainty and the external challenges (such as mixed meal contents, physical exercise, physiological stress and intercurrent illness) that people with Type 1 Diabetes Mellitus (T1DM) may be exposed to outside the clinical environment. The principal research objective is to assess the safety and efficacy of a closed-loop system for T1DM compared to standard insulin pump therapy (open-loop). The primary outcome from the studies will be % time spent with a glucose concentration in the target range (3.9-10.0mmol/l). This outcome incorporates safety as it ensures subjects do not have low or high glucose excursions and is the principal measure of efficacy for closed-loop insulin delivery systems in the scientific literature. Other measured outcomes will be % time spent in euglycaemia (3.9-7.8mmol/l), % time spent in hypoglycaemia (\<3.9mmol/l), % time spent in hyperglycaemia (\>10mmol/l), mean venous blood and sensor glucose, glycaemic variability as measured by standard metrics (Standard Deviation, Continuous Overlapping Net Glycaemic Action, Lability Index, J-Index, Glycaemic Risk Assessment Diabetes Equation, Mean Of Daily Differences, Mean Amplitude of Glucose Excursion, Average Daily Risk Range, M-VALUE, Mean Average Glucose), glycaemic risk as measured by Low Blood Glucose Index (LBGI) and High Blood Glucose Index (HBGI), closed-loop error grid analysis, glucose area under the curve. All measures have been previously published and validated. This clinical trial protocol assesses the artificial pancreas system in three separate sub-studies: 1. In a bi-hormonal (insulin and glucagon) configuration 2. During and after exercise with bi-hormonal closed loop, and standard insulin opened loop 3. During and after meals of mixed composition with bi-hormonal closed loop, and standard insulin opened loop

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