Despite advances in insulin technology and the development of different regimens including multiple daily injections (MDI), there still remain a group of patients with Type 1 diabetes who pose significant management problems. Problems include erratic blood glucose readings, unpredictable and debilitating hypoglycaemia and issues with injection sites. For this group of patients, an insulin pump is an option.
An insulin pump is a pager sized device worn continuously by the patient. It contains a reservoir of insulin which is infused continuously via a giving set inserted subcutaneously, usually into the lower abdomen. The insulin infusion is usually divided into a basal rate with boluses given at meal times. Whilst this may sound like a technological method of MDI, the increasingly sophistication means that basal and bolus rates can be programmed separately, giving a level of flexibility and accuracy greater than a subcutaneous injection. The basal rate can be changed depending on the time of day whilst the bolus can be tailored specifically to the type of food. Of course all of this requires an increased level of training and education for the patient both on how to manage the pump as well as carbohydrate counting and dietary knowledge. Usually patients need to test their blood glucose more intensively in order to adjust their insulin rate although there are an increasing number of sophisticated pumps which link to continuous glucose sensors via Bluetooth in a ‘closed loop’ system.
The majority of patients with a pump feel more empowered to self manage their blood glucose levels especially given the freedom from injections. However, others find the thought of permanently being attached to a device difficult to manage. This includes certain activities and some limitation on clothing. Furthermore, all patients will need to be able to switch to injections should any pump issues arise unexpectedly.
As expected, NICE has issued guidance (although surprisingly not updated since 2008). Currently NICE recommend insulin pumps for patients whose attempts to achieve target haemoglobin A1c (HbA1c) levels with multiple daily injections (MDIs) result in the person experiencing disabling hypoglycaemia and for patients whose HbA1c levels have remained high (that is, at 8.5% or above) on MDI therapy (including, if appropriate, the use of long-acting insulin analogues) despite a high level of care. They are not recommended for patients with Type 2 diabetes.
Dr Mark Freeman