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Dr Araz Rawshani

Automated insulin pumps: new promising study

It is very difficult for people with type 1 diabetes to achieve the goals of glycemic control (blood sugar). Balancing blood sugar, insulin and the carbohydrate content of meals is a constant challenge. For many years, patients and healthcare professionals have been hoping for new technology that would automate insulin dosing and regulate blood sugar. Such an aid, which takes care of blood sugar completely automatically, would revolutionize the life of anyone who has type 1 diabetes. Today, a new study was published in the most prestigious medical journal (Brown et al) showing that self-controlling, almost fully automatic, insulin pumps are both highly effective and safe. The results of the study are likely to affect treatment guidelines for many years to come. Here the main results of the study are discussed.

Insulin pumps, continuous blood glucose meters and self-controlling pumps

The use of an insulin pump and continuous blood glucose meter (CGM) can make life and everyday life easier for people with type 1 diabetes. More and more patients have pumps and/or CGM (blood glucose meters). The most modern insulin pumps and blood glucose meters can additionally communicate with each other. Then the insulin pump can be controlled by the blood glucose meter. Such a device is called self-controlling insulin pump. These devices have more and more smart functions that can adjust, stop or increase the supply of insulin. For example, insulin may be stopped in case of hypoglycaemia (blood sugar fall).

The term artificial pancreas is used to describe an apparatus that acts as an artificial pancreas. The self-controlling insulin pump is a type of artificial pancreas and the researchers aim is that the pump should become fully automatic and be able to counter both high and low blood sugar. In English, the name closed-loop is instead used, which aims to make the system end in the sense that it handles both infusions and blood glucose measurements. In Sweden we use the name self-controlling insulin pump.

Self-controlling insulin pumps can counteract blood sugar fall (hypoglycaemia) and blood sugar rise (hyperglycaemia). These systems therefore consist of pump, CGM and an algorithm that continuously adjusts insulin delivery. When the blood sugar rises, the pump increases the insulin infusion and vice versa. Some appliances are additionally equipped with glucagon. Glucagon is a hormone that increases blood sugar by stimulating the liver to release glucose stored there.

A hybrid is a self-controlling insulin pump that manages basal insulin but requires the individual to enter carbohydrate amounts and bolus doses.

Read more: Technical devices for the treatment of diabetes

Recent studies: self-controlling pumps are the future

A further large study has now been published comparing a self-controlling insulin pump with a less automated insulin pump connected to a CGM. The study included children, adolescents and adults with type 1 diabetes, and there were both people with good and poor glycaemic control. The study showed that the more automated self-controlling pump was safe, efficient and did not involve increased risks of hypoglycaemia. People who received the more automated self-controlling insulin pump could enjoy longer periods of well-controlled blood sugar. At present, only one such self-controlling insulin pump is on the market, namely Medtronic Minimed 670G. However, Tandem Control IQ was used in this study.

Tandem Control IQ is dependent on the Dexcom G6 sensor (which is calibration-free, meaning no need to stick your fingers) and has features to prevent hypoglycaemia, correction bolus and intensified insulin delivery during the night to improve blood sugar in the morning. The Tandem Control IQ group was compared to a group (the “control group”) of patients who received a self-controlling pump connected to a CGM which, however, did not have the additional features of Tandem Control IQ. The study included a total of 168 patients aged 14 to 71 years. Summary of the results of the study follows:

Those who received Tandem Control IQ increased their time within the target blood sugar level from 61% to 71%. The effect came immediately after initiation of treatment with Tandem Control IQ. The control group made no improvement.The Tandem Control IQ group had better blood sugar throughout the day and most of the night.A patient with Tandem Control IQ received ketoacidosis, and this was caused by the failure of the infusion device. study.

Key results

These results are very important and clinically significant. The group receiving the more automated self-controlling insulin pump (Tandem Control IQ) increased its time within the target level by a whole 10%. We know from previous studies that increasing the time outside the target level by 10% increases the risk of retinopathy by 65% and the risk of microalbuminuria rises by 40% (Beck et al).

Although much work remains before patients have fully automated insulin pumps, the development is moving very fast now. People with diabetes will soon be able to enjoy a much more comfortable life with less need to manually manage their blood sugar, while blood sugar and the risk of complications will decrease thanks to the new technology.

References

Brown SA, Kovatchev BP, Raghinaru D, et al. Six-month randomized, multicenter trial of closed-loop control in type 1 diabetes. N Engl J Med. DOI: 10.1056/1907863.

Foster NC, Beck RW, Miller KM, et al. State of type 1 diabetes management and outcomes from the T1D Exchange in 2016-2018. Diabetes Technol Ther 2019; 21:66 -72.Weisman A, Bai JW, Cardinez M, Kramer CK, Perkins BA.

Effect of artificial pancreas systems on glycaemic control in patients with type 1 diabetes: a systematic review and meta-analysis of outpatient randomised controlled trials. Lancet Diabetes Endocrinol 2017; 5:501 -12.

Bekiari E, Kitsios K, Thabit H, et al. Artificial pancreas treatment for outpatients with type 1 diabetes: systematic review and meta-analysis. BMJ 2018; 361:k1310.

Beck RW, Bergenstal RM, Riddlesworth TD, et al. Validation of time in range as an outcome measure for diabetes clinical trials. Diabetes Care 2019; 42:400 -5.

Boughton CK, Hovorka R. Is an artificial pancreas (closedloop system) for type 1 diabetes effective? Diabet With 2019; 36:279-86

This is a summary of the article Towards automatic insulin delivery by Daniela Bruttomesso in The New England Journal of Medicine.

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