Insulin pump therapy
This is an alternative to injecting insulin is to use continuous subcutaneous insulin infusion (CSII) with an insulin pump. This is where there is a continuous infusion of rapid /short-acting insulin delivered by a short cannula under the skin with boluses of insulin given to cover meals. There are advantages and disadvantages to pump therapy and these need to be discussed with the diabetes team. In the UK, children are prescribed pump therapy often within 6 months of diagnosis.
There are two types of pump therapy:
- the open-loop therapy where insulin administration is manually controlled
- the hybrid closed-loop system where insulin delivery is automatically regulated.
A study (The Lancet Diabetes and Endocrinology, 13 February 2025) showed that hybrid closed-loop systems offer improved long-term blood sugar values (HbA1c levels) and a lower risk of hypoglycaemic coma, but lead to a higher rate of diabetic ketoacidosis.
Until recently, the effect of insulin delivery in hybrid closed-loop systems on the risk of acute diabetes complications in people with Type 1 diabetes has been unclear. Researchers have investigated whether the rates of severe low blood sugar levels (hypoglycaemia) and diabetic ketoacidosis (DKA) are lower with hybrid closed-loop insulin therapy compared with open-loop pump therapy.
The researchers looked at data from 14,000 young people with an average age of 13.2 years who had had Type 1 diabetes for a year. 7,088 used a hybrid closed-loop system and 6,834 used an open-loop system.
Results
- People using hybrid closed-loop therapy had a significantly lower rate of hypoglycaemic coma than those using open-loop therapy.
- Those in the hybrid closed-loop group had a significantly lower HbA1c level and a higher percentage of time in the target glucose range of 3.9 to 10.0 mmol/L. Their glycaemic variability was also lower and there was no significant difference in the rate of severe hypoglycaemia.
- Those using a hybrid closed-loop system had a higher rate of diabetic ketoacidosis (DKA) than those using open-loop therapy. DKA rates were reported as 5.25 per 100 patient-years in the hybrid closed-loop group versus 1.53 in the open-loop group.
- The rate of DKA was particularly high in people with an HbA1c level of 8.5% or higher in the closed-loop therapy group.
The researchers stated that this does not mean hybrid closed-loop systems are unsafe by default but, as it was associated with a higher DKA rate, user education, troubleshooting, infusion set management and clear sick-day rules are important.
For families and young people using closed-loop systems, the message is: automated insulin delivery can improve day-to-day control, but it does not remove the need for vigilance, especially when something goes wrong.
