Scientists in Cambridge have made a significant step towards developing a so-called "artificial pancreas" system for managing type 1 diabetes in children. The team has developed and successfully tested a new algorithm, providing a stepping stone to home testing for the artificial pancreas.
The new study -- funded by Juvenile Diabetes Research Foundation (JDRF) and published in The Lancet -- shows that using an artificial pancreas system overnight can significantly reduce the risk of hypoglycemia, when blood glucose levels drop dangerously low, while sleeping. These so-called "hypos" are a major concern for children and adults with type 1 diabetes.
An artificial pancreas system combines a continuous glucose monitor and an insulin pump, both already on the market, and uses a sophisticated algorithm to calculate the appropriate amount of insulin to deliver based on the real-time glucose readings.
As well as obviating the need for multiple daily finger prick tests and insulin injections, the artificial pancreas should offer better control of blood glucose levels overnight.
In the new study, 17 children and teenagers aged between 5 and 18 with type 1 diabetes were studied during 54 nights in hospital. The team measured how well the artificial pancreas system controlled glucose levels compared with the children's regular continuous subcutaneous insulin infusion (CSII) pump, which delivers insulin at preselected rates.
The study included nights when the children went to bed after eating a large evening meal or having done early evening exercise. Both are challenging to manage, a large evening meal because it can lead to so-called "insulin stacking" and, as a result, a potentially dangerous drop in blood glucose levels later in the night, and late afternoon or early evening exercise because it increases the body's need for glucose in the early morning and can therefore increase the risk of night time hypoglycaemia.
The pooled results showed the artificial pancreas kept blood glucose levels in the normal range for 60% of the time, compared with 40% for the CSII. The artificial pancreas halved the time that blood glucose levels fell below 3.9mmol/l -- the level considered as mild hypoglycaemia. It also prevented blood glucose falling below 3.0mmol/l, which is defined as significant hypoglycaemia, compared with nine hypoglycaemia events in the control studies.
According to lead author Dr Roman Hovorka of the Institute of Metabolic Science at the University of Cambridge: "Our results show that commercially-available devices, when coupled with the algorithm we developed, can improve glucose control in children and significantly reduce the risk of hypos overnight."
"This is the first randomised study showing the potential benefit of the artificial pancreas system overnight using commercially-available sensors and pumps. Our study provides a stepping stone for testing the system at home."
Type 1 diabetes is a chronic, life threatening condition which is on the increase in the UK, particularly in the under fives. Children and adults require multiple daily insulin injections or pump infusions and many finger prick blood tests each day. However, treatment with insulin brings with it the risk of hypoglycaemia, one of the most feared short-term complications of type 1 diabetes for children and their parents.
Recent technological developments in blood glucose monitors and devices for continuous administration of insulin -- such as those used in this study -- can improve blood glucose control, but more needs to be done.
Commenting on the results Karen Addington, Chief Executive of JDRF said: "This study is proof of principle that type 1 diabetes in children can be safely managed overnight with an artificial pancreas system. We need to redouble our efforts to move the artificial pancreas from a concept in the clinic to a reality in the home of children and adults with type 1 diabetes."
- Roman Hovorka et al. Closed-loop insulin delivery in children and adolescents with type 1 diabetes. The Lancet, February 5, 2010
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