What is the artificial pancreas?
In people without diabetes, pancreatic islet cells detect glucose in the blood, and release insulin or glycogen to keep the glucose level in a safe range.
All people with type 1 diabetes use a treatment ‘loop’ to mimic this function the best we can – at present this involves:
- a pump or insulin pen (for insulin delivery)
- a blood glucose monitor and maybe CGM (for glucose level assessment), and
- our brains and fingers to calculate the dose required and deliver it to complete the loop
‘Closing the loop’ means making it happen automatically. This means a calculator or ‘algorithm’ is needed to replace our brains and fingers.
In a hybrid closed loop or artificial pancreas system, the algorithm adjusts the basal (background) insulin every few minutes as necessary, to keep the glucose within a target range. At mealtimes, the user counts their carbohydrate and keys it in to the algorithm, which then decides how much insulin is required and sends an instruction to a pump to deliver the dose.
This technology has progressed in the last 10 years:
- first came an insulin pump with low glucose suspend when CGM detects hypoglycaemia,
- next there was predictive low glucose suspend when CGM detects glucose is falling towards hypoglycaemia,
- current systems available are called hybrid closed loop – predictive high and low minimiser work alongside an automated basal rate (though some systems require a programmed basal rate as a starting point) but meal-time boluses must be programmed manually,
- in the future we look forward to having fully automated closed loop with insulin only – needs no programming by the user,
- and eventually fully automated closed loop with insulin and glucagon.
Where are we now?
Current commercial systems are called hybrid closed loop – predictive high and low minimisers work alongside an automated basal rate (though some systems require the user to programme a basal rate as a starting point) but meal-time boluses must be programmed manually.
People who follow a very low carbohydrate diet have been able to operate hybrid closed loop systems without meal-time input.
Systems available in the UK:
- CamAPS FX hybrid closed loop uses a DANA insulin pump and Dexcom CGM. (This system comes from JDRF-funded research at Addenbrookes). Licenced for those aged 1+
- Medtronic 670G + Guardian sensors hybrid closed loop uses Medtronic insulin pump and sensors. This system adjusts the basal rate to minimise predicted highs or and low glucose. Licenced for those aged 7+
- Medtronic 780G + Guardian sensors hybrid closed loop uses Medtronic insulin pump and sensors, and minimises high and low glucose by adjusting the basal rate and delivering correction boluses. Licenced for those aged 7+
- Control IQ hybrid closed loop uses Tandem t:slim insulin pump and Dexcom CGM. Licenced for those aged 4+
- Please note OmniPod 5 hybrid closed loop is not yet available in the UK. It will use a new OmniPod pump and Dexcom G6 sensors. Watch this space for UK launch information!
Earlier generations / systems that are less automated:
- Medtronic 640G + Enlite or Guardian sensors with predictive low glucose suspend
- Medtrum A7+ + Medtrum sensor has predictive low glucose suspend
- Basal IQ has predictive low glucose suspend and uses Tandem t:slim X2 insulin pump and Dexcom CGM
Predictive low glucose suspend will temporarily turn off the delivery of insulin when the sensor detects that the glucose level is likely to dip into a hypo, therefore preventing the hypo from happening or minimising it’s severity.
High glucose minimiser will activate when the sensor detects that the glucose level is likely to rise above the target. This may be by a temporary basal rate increase alone, small correction boluses, or a combination of both.
Can I get a closed-loop system on the NHS?
At present, in order to get a fully funded closed-loop system on the NHS, you will need to meet criteria for both pump funding and for CGM funding (see “Useful information” below). However, meeting criteria for CGM funding doesn’t necessarily mean it will be granted to you and CGM is not yet routinely funded.
If you can get a pump funded but can’t get funding for CGM, it is possible to ‘top up’ the system by paying for the CGM yourself.
NICE is currently appraising hybrid closed loops systems. The result is expected to be published in mid 2022.
In January 2022 the Scottish Health Technologies Group (SHTG) published recommendations that support wider use of closed-loop systems.
The Scottish Health Technologies Group (SHTG) is a national health technology assessment (HTA) agency which provides advice to NHSScotland on the use of new and existing health technologies (excluding medicines), likely to have significant implications for people’s care. NHSScotland is required to consider its advice.
The SHTG recommends:
- clinicians should pro-actively discuss with all patients with type 1 diabetes, the suitability of a closed loop system for their individual circumstances.
- single hormone closed loop systems (ie insulin-only) should be available to people with type 1 diabetes (children and adults) who:
• under their current diabetes care plan, continue to have poor blood sugar control, a high risk of severe hypoglycaemia, or impaired awareness of hypoglycaemia, or
• experience severe diabetes-related distress, measured using a validated tool, that adversely affects quality of life or their ability to manage diabetes, and which is likely to
be improved by moving to a closed loop system.
The following people with type 1 diabetes, who achieve the desired blood sugar control, should be supported to remain on their current diabetes care plan subject to their circumstances and
quality of life:
• people using finger prick testing plus multiple daily insulin injections
• people using flash (FreeStyle Libre®) glucose monitoring plus multiple daily insulin injections
• people using CGM plus multiple daily injections, and
• people using flash (FreeStyle Libre®) glucose monitoring plus an insulin pump.
People who are currently using both a CGM sensor and an insulin pump should be offered a closed loop system.
Useful information until then
DTN series of videos on sensor augmented pump therapy / hybrid closed loop (DTN is the Diabetes Technology Network UK, an organisation designed to support UK health care professionals who are involved in the delivery of technologies designed to improve the lives of people living with diabetes)
For information on systems in development or systems that are not yet available in the UK, watch: