By Josie Clarkson, Research Communications Lead, JDRF

Published: 4 July 2023

People with type 1 diabetes have to make countless decisions every day to try to keep their blood sugar levels within a healthy range. Living with type 1 diabetes is relentless and requires constant management. Someone with type 1 could do all the right things to manage their diabetes but their blood sugar levels could still be too high, too low, or a rollercoaster between both extremes, which can be fatal. Long term, these fluctuations can lead to heart failure, loss of limbs, kidney failure and loss of eyesight.

With no cure, type 1 diabetes represents a huge unmet healthcare need . While we hunt for a cure for the condition, a priority for many people  is to be able to manage their type 1 diabetes effectively and to relieve some of its mental burden. Now, thanks to nearly two decades of research funded by JDRF, the type 1 diabetes research charity and member of AMRC, a treatment that does just that is coming to the NHS. The treatment is called hybrid closed loop (HCL) and is also referred to as the ‘artificial pancreas’.

To understand what HCL is, we need to learn a bit about the technology that is currently available in the UK to help people with type 1 diabetes manage their condition. Continuous glucose monitors (CGMs) are sensors attached to the skin with a small needle that measures a person’s blood sugar levels. Insulin pumps are devices that hold insulin and can deliver it via a small tube into the person wearing it, so they don’t have to inject themselves every time they need insulin.

What is HCL?

HCL is a system that connects the user’s CGM to their insulin pump via an app in their smartphone. It uses blood glucose readings from the CGM to tell the insulin pump when to administer insulin, and what dose to give. It uses artificial intelligence to learn about the individual’s type 1 diabetes (because the condition varies from person to person) and tweaks its responses accordingly.


“This treatment breaks new ground in health technology. It lifts the burden of this relentless condition and reduces the risk of potentially fatal high and low glucose levels and long-term complications of diabetes. It’s a beautifully adaptive piece of code which will save lives and heartbreak, as well as long-term saving the NHS on costs of cardiovascular and retinal surgery and kidney dialysis and transplants.”

“JDRF has funded research into HCL for over 15 years. We have campaigned and advocated for this treatment to be made available for people with type 1 diabetes.”

Hilary Nathan, JDRF Director of Policy


Where did HCL start?

JDRF began funding a researcher named Professor Roman Hovorka at the University of Cambridge back in 2006 to develop an HCL app. Since then, we have continued to fund clinical trials of his HCL model on people with type 1 of different ages, both in the lab and under normal conditions, including overnight. All these tests were needed to ensure the technology is safe to use and can benefit as many people as possible.


“In concert with JDRF, our mission is to alleviate the burden of type 1 diabetes and improve health outcomes in people of all ages. Our clinical study data evaluating hybrid closed loop systems show a broad range of benefits including increased time in range, reduced HbA1c, reduced mean sensor glucose, and often reduced hypoglycaemia burden. Importantly, we have observed improved quality of life including improved sleep, less time spent on diabetes management, reduced family stress, greater independence for children and teenagers, and greater meal freedom. I look forward to many more people having access to the technology in the near future.”  

Professor Roman Hovorka, University of Cambridge


While Professor Hovorka was conducting clinical trials, we funded Dr Conor Farrington (also at University of Cambridge) to interview diabetes healthcare professionals to learn how they feel about hybrid closed loop systems. He found that clinicians thought that HCL would improve the consistency of their patients’ blood glucose levels as well as their overall quality of life. However, they were concerned that the system still requires some manual input from the user, such as entering information about meals and exercise. They were also worried that people with type 1 would lose the skills to manage their diabetes without the technology, in case of emergencies.

Where are we now?

Dr Farrington’s research, along with an NHS pilot of HCL was used to accelerate the impact HCL could have for patients by helping overcome the potential barriers to clinicians adopting the technology. Now, NICE (which provides evidence-based recommendations for the NHS) has released draft guidelines recommending that HCL should be available on the NHS to over 100,000 people. JDRF along with others in the type 1 diabetes community commented on the draft proposals and are now waiting for NICE to announce their updated guidelines in Autumn 2023.


“From day one it was amazing. Before the closed loop system, I would experience a lot of highs, which I’d then overcorrect, go low and then eat a lot of sugar. All of that was eradicated. It has completely changed my life. It. Before, if I had a meeting at work, I’d have to decide whether I wanted to be running a little high. I don’t have to think like that anymore. The technology takes away all of the second thoughts I have about living my life.”

Yasmin, who has type 1 diabetes and took part in the NHS pilot of HCL


You can read more about hybrid closed loop and JDRF’s research into the technology on the JDRF website.