Closed loop systems in type 1 diabetes

People with type 1 diabetes, whose immune systems destroy their insulin producing pancreatic cells, must inject insulin to stay alive. Tight control of plasma glucose prevents or delays complications such as retinopathy and nephropathy; it also avoids hypoglycaemia, the most common adverse effect of insulin treatment, which can cause, at worst, disorientation and death.

To achieve glycaemic control, people need either multiple daily injections (including long acting basal insulin once or twice daily, plus short acting insulin with meals) or an insulin pump (continuous subcutaneous insulin infusion). They must monitor blood glucose concentrations (generally by finger pricking), and adjust their insulin doses based on blood glucose, food and alcohol intake, and physical activity.1 They should learn to adjust insulin doses through structured education programmes such as DAFNE (dose adjustment for normal eating),2 or similar programmes for children and adolescents.

The key to achieving good control is self-management. But that is hard, even for the best motivated and educated individuals. Most people with type 1 …