Martin de Bock; Tim Jones; Liz Davis
Study Staff: Julie Dart Carolyn Berthold
Type 1 Diabetes (T1D) affects over 130,000 Australians and 22 million people worldwide and is caused by the body’s immune system attacking the cells of pancreas that produce insulin. Subsequently, lifelong external insulin needs to be given in order to maintain a healthy blood sugar levels.
An individual’s insulin requirement may vary greatly according to food intake, time of day, stress, fitness, hormones, illness and physical activity. At present, decisions regarding insulin dosing are made by the patient with support from their medical team. A mismatch between an individual’s insulin requirements and insulin delivery can result in acute conditions such as severe hypoglycaemia (low blood glucose levels) that result in seizures and potentially death. While, long term mismanagement of blood glucose can lead to chronic illnesses such as cardiovascular disease, kidney failure, blindness and nerve damage.
The Artificial Pancreas or Closed Loop Glucose-Sensing Insulin-Delivery System is a novel technology designed to overcome the limitations of current therapeutic approaches. It hasthree main components: i) an insulin pump which delivers subcutaneous rapid-acting insulin flexibly and precisely, ii) a subcutaneous glucose sensor continuously measuring interstitial fluid glucose levels which are displayed on the pump screen in real time and iii) and a control algorithm that processes the glucose sensor data and controls insulin delivery via the insulin pump.
Previously closed loop systems have been evaluated in clinical trial centres, and early results from outpatient studies are starting to emerge that demonstrate improved time spent in the healthy glucose range with reduced incidence hypoglycaemia. The ultimate aim of our research is the progression to long term outpatient study using closed loop technology. However a stepwise approach, with safety monitoring at each point is paramount to achieving this objective.
The purpose of this study is to evaluate the safety of new system called the Medtronic MinimedTM 670G that has been designed for long term outpatient use. Vigorous in-clinic testing simulating hypoglycaemic inducing scenarios (exercise, and over-reading sensor) is required to assess safety before a pivotal long term outpatient study can be performed. This study will evaluate the efficiency of the system in 12-50 year old Type 1 diabetic patients in a 4 day in-clinic study during which they will be asked to wear the system and constantly monitored while undertaking potentially hypoglycaemia inducing tasks such as exercise. The data collected in this study will in turn be used to inform future long term studies of this technology in the wider community in order to contribute to reducing the burden of Type 1 diabetes on the health system.
Funder: Diabetes Research Australia Trust