The Bio-Inspired Artificial Pancreas for the Home

In addition to assessing the closed-loop insulin delivery system on its own, the study aims to evaluate the system when combined with a personalised bolus calculator that adapts over time. Standard bolus calculators are widely used in type 1 diabetes self-management to calculate insulin boluses at mealtimes and are incorporated in all insulin pumps and in some glucose meters. A standard bolus calculator uses a generic formula taking into account the target glucose level, current glucose level, carbohydrate content of meal (grams), insulin: carbohydrate ratio (the amount of carbohydrate (grams) covered by 1 unit of insulin), insulin sensitivity factor (the reduction in blood glucose by 1 unit of insulin) and insulin-on-board (IOB, the remaining active insulin from the previous bolus). Some bolus calculators additionally consider parameters such as exercise, but all lack the ability to automatically adapt over time to respond to individual needs. Finally, the study aims to compare the closed-loop insulin delivery system to standard pump therapy (also known as an open-loop insulin delivery system) in combination with continuous glucose monitoring (referred to as sensor augmented pump). The Diabetes Technology group at Imperial College have developed a unique closed-loop insulin delivery system known as the Bio-inspired Artificial Pancreas (BiAP) and a personalised bolus calculator known as the Advanced Bolus Calculator for Diabetes (ABC4D). Overview of the complete closed-loop system (artificial pancreas) used in this study is as follows: 1. A commercially available continuous subcutaneous glucose sensor (Dexcom G5 CGM system). 2. The BiAP control algorithm implemented in a low-power handheld device (developed at Imperial College) 3. An insulin infusion pump (Tandem t:slim) for insulin delivery. In one part of the study the closed-loop system will be evaluated in combination with: 4. The ABC4D adaptive bolus calculator implemented in a smartphone (as an app) All the components will be tested together as a combined system.