Scientists have successfully trialled an artificial pancreas for use by patients living with type 2 diabetes. Closed loop systems (often called an 'artificial pancreas') have been described by some as the 'holy grail' of diabetes management. In fact, earlier this week, recognising the benefits of these systems – which include better blood glucose control, freedom from finger-prick testing, less worry, and better quality of life for those with diabetes and their loved ones – the National Institute for Health and Care Excellence (NICE) issued draft recommendations that hybrid closed loop systems should be available on the NHS for those struggling to control their type 1 diabetes, and also for people who are pregnant or planning a pregnancy.
Diabetes UK estimates that in the UK more than 4.9 million people have diabetes, of whom 90% have type 2 diabetes, and this is estimated to cost the NHS £10 bn per year.
Dr Charlotte Boughton from the Wellcome-MRC Institute of Metabolic Science at the University of Cambridge, who co-led the new study, said: "Many people with type 2 diabetes struggle to manage their blood sugar levels using the currently available treatments, such as insulin injections."
The authors of the study, published in Nature Medicine, commented that fully closed-loop systems are more convenient for the user. Fully closed-loop systems differ to hybrid closed loop systems by not requiring user input (carbohydrate announcement and prandial insulin boluses) at mealtimes.
The team of researchers from the Wellcome-MRC Institute of Metabolic Science at the University of Cambridge 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 (CamAPS HX) developed by the team. The app is run by an algorithm that predicts how much insulin is required to maintain glucose levels in the target range.
"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," explained the authors.
Time in Target Glucose Range Doubled
The team of researchers had previously shown that an artificial pancreas run by a similar algorithm is effective for patients living with type 1 diabetes, from adults through to very young children. They had also successfully trialled the device in patients with type 2 diabetes who required kidney dialysis.
For the open-label, single-centre, randomised crossover study, they wanted to investigate the effect of the device in a wider population of people living with type 2 diabetes, who did not require kidney dialysis.
Between 16 December 2020 and 24 November 2021 the researchers recruited 26 patients with type 2 diabetes (7 females and 19 males, mean age 59 years, mean baseline HbA1c 9.0) from Addenbrooke's Hospital diabetes clinic and a local GP surgery.
Patients were randomly allocated to one of two groups: the first group trialled the artificial pancreas for 8 weeks and then switched to standard therapy of multiple daily insulin injections; the second group followed this control therapy first and then switched to the artificial pancreas after 8 weeks, with a 2-4 week wash-out period in between.
The primary endpoint was the proportion of time in target glucose range: 3.9 to 10.0 mmol/L.
The device doubled the amount of time patients were in the target range for glucose compared with standard treatment (66.3% with closed-loop versus 32.3% with control), which they said equated to "an additional 8 hours per day". It also halved the time spent experiencing high glucose levels (33.2% with closed-loop versus 67.0% with control).
Average glucose levels fell from 12.6 mmol/L when using control therapy to 9.2 mmol/L whilst using the artificial pancreas. Also, HbA1c was lower following closed-loop use (7.3%) compared with following control therapy (8.7%).
Hypoglycaemia Fears Allayed
The authors highlighted that a major contributor to the "clinical inertia in escalation of insulin therapy" among healthcare professionals, and a feared side-effect of insulin among people with type 2 diabetes, is the risk of hypoglycaemia. In the study the researchers found that the fully closed-loop insulin delivery improved glucose control "without increasing hypoglycaemia" compared with standard insulin therapy.
Dr Aideen Daly, Wellcome-MRC Institute of Metabolic Science, said: "One of the barriers to widespread use of insulin therapy has been concern over the risk of severe 'hypos'. But we found that no patients on our trial experienced these and patients spent very little time with blood sugar levels lower than the target levels."
The authors acknowledged some limitations of the study, which included that study participants were recruited from a single centre and one general practice, and that participants were not ethnically diverse, with only one participant not of White ethnicity.
While the present study demonstrated glycaemic benefits over the 8-week intervention period, the results should "not be generalised" beyond this period, they pointed out. "Larger randomised controlled trials with diverse populations and longer follow-up" were required to ensure generalisability across a wider target population, and to determine if it is a cost-effective approach which provides sustained benefits for people with type 2 diabetes requiring insulin therapy.
Feedback from participants suggested they were happy to have their glucose levels controlled automatically by the system, and 9 in 10 (89%) reported spending less time managing their diabetes overall.
Dr Boughton effused that the artificial pancreas can provide a "safe and effective approach" to help those with type 2 diabetes, and bolstered that "the technology is simple to use and can be implemented safely at home".
Funding for the study was provided by National Institute for Health and Care Research (NIHR) Cambridge Biomedical Research Centre.
