The burden of type 2 diabetes is far reaching, with an estimated 415 million people affected worldwide and an estimated annual global health expenditure of US $760 billion. Intensive glycemic management to achieve the target glycated hemoglobin (HbA1c) value of less than 7% (53 mmol mol−1) is supported by good-quality evidence, but glucose control remains inadequate globally.
In the initial stages of the disease, most people with type 2 diabetes require a combination of lifestyle interventions and pharmacological therapy, benefiting from the availability of an increasing number of oral antihyperglycemic agents. Progressive beta-cell depletion and adoption of the early intensive glycemic-control paradigm mandate initiation of insulin therapy, which improves glycemic control but increases the risk of hypoglycemia
Closed-loop insulin delivery offers a new, glucose-responsive method of glucose control and comprises a continuous glucose monitor, an insulin pump and a control algorithm that automatically modulates subcutaneous insulin delivery. Hybrid closed-loop systems, with a requirement for carbohydrate announcement and prandial insulin boluses, are commercially available for people with type 1 diabetes.
Artificial pancreas successfully trialed for use by type 2 diabetes patients
Researchers from the Wellcome-MRC Institute of Metabolic Science at the University of Cambridge have developed an artificial pancreas that can help maintain healthy glucose levels. The device combines an off-the-shelf glucose monitor and insulin pump with an app developed by the team, known as CamAPS HX. This app is run by an algorithm that predicts how much insulin is required to maintain glucose levels in the target range.
The team reported the first trial of the device in a wider population living with type 2 diabetes. Unlike the artificial pancreas used for type 1 diabetes, this new version is a fully closed loop system, whereas patients with type 1 diabetes need to tell their artificial pancreas that they are about to eat to allow adjustment of insulin, for example, with this version they can leave the device to function entirely automatically.
The researchers recruited 26 patients from the Wolfson Diabetes and Endocrine Clinic at Addenbrooke’s Hospital, part of Cambridge University Hospitals NHS Foundation Trust, and a local group of GP surgeries. Patients were randomly allocated to one of two groups , the first group would trial the artificial pancreas for eight weeks and then switch to the standard therapy of multiple daily insulin injections; the second group would take this control therapy first and then switch to the artificial pancreas after eight weeks.
The team used several measures to assess how effectively the artificial pancreas worked. The first was the proportion of time that patients spent with their glucose levels within a target range of between 3.9 and 10.0mmol/L. On average, patients using the artificial pancreas spent two-thirds (66%) of their time within the target range, double that while on the control (32%).
A second measure was the proportion of time spent with glucose levels above 10.0mmol/L. Over time, high glucose levels raise the risk of potentially serious complications. Patients taking the control therapy spent two-thirds (67%) of their time with high glucose levels,this was halved to 33% when using the artificial pancreas.
Average glucose levels fell — from 12.6mmol/L when taking the control therapy to 9.2mmol/L while using the artificial pancreas.
The app also reduced levels of a molecule known as HbA1c. By measuring HbA1c, clinicians are able to get an overall picture of what a person’s average blood sugar levels have been over a period of weeks or months. For people with diabetes, the higher the HbA1c, the greater the risk of developing diabetes-related complications. After the control therapy, average HbA1c levels were 8.7%, while after using the artificial pancreas they were 7.3%.
The team now plan to carry out a much larger multicentre study to build on their findings and have submitted the device for regulatory approval with a view to making it commercially available for outpatients with type 2 diabetes. No patients experienced dangerously-low blood sugar levels (hypoglycaemia) during the study.
Aideen B. Daly, Charlotte K. Boughton, Munachiso Nwokolo, Sara Hartnell, Malgorzata E. Wilinska, Alina Cezar, Mark L. Evans, Roman Hovorka. Fully automated closed-loop insulin delivery in adults with type 2 diabetes: an open-label, single-center, randomized crossover trial. Nature Medicine, 2023; DOI: 10.1038/s41591-022-02144-z