5 hybrid closed-loop systems that type 1 diabetics should ask their consultant about
5 hybrid closed-loop systems that anyone with a dodgy pancreas should know about
In my 26 years of living with type 1 diabetes, hybrid closed-loop (HCL) technology is the best medical advancement I’ve been fortunate to receive. HCL is the latest wave in diabetes management, and it makes living with the condition a whole lot easier.
Essentially, the system requires a continuous glucose monitor (CGM), an insulin pump, and a specific algorithm that tells the pump to either suspend the insulin or give a bit more, depending on the CGM readings.
Sounds pretty cool, right? Read on for more explanation…
The pros
These systems take some of the burden of managing t1d away and research shows an improvement in quality of life.
These systems tend to work really well overnight, meaning that a good chunk of someone’s time-in-range can be optimised (sleep accounts for about 1/3 of our TIR!).
Fewer finger pricks (due to the CGM) and no injections (due to the pump) - in theory.
Increasing flexibility around meals and exercise.
The cons
Like any other technology, these systems are not immune to failures or errors, which can be disheartening and troubling for those relying on the system to, ya know, like. Live.
You’ll need to be attached to devices 24/7 which can be a big transition for those currently on multiple dose injections.
There’s a learning curve for anyone moving to HCL tech and this can take time and patience.
You’ll still need to input carbohydrate amount, pre-bolus, and tell the pump to bolus insulin.
A note on linguistics - this is not an ‘artificial pancreas’
You may have seen the press, or other outlets, referring to this technology as an ‘artificial pancreas’. Whilst that name is arguably more catchy than ‘hybrid closed-loop’, it’s an inaccurate description of what HCL systems are. Artificial pancreas implies the person with diabetes doesn’t need to do anything, but HCLs do require a large amount of human input.
This new-wave treatment option does reduce the burden on the person living with type 1, but it doesn’t extinguish completely.
See the last point on the ‘cons’ list above.
Can I get a HCL system on the NHS?
After a successful NHS England pilot in November 2023, the National Institute for Health and Care Excellence (NICE) recommended that HCL technology should be rolled out to thousands of people with type 1 diabetes over the next 5 years.
This is great news, though in reality the access to this life-changing tech is still patchy. According to NICE, hybrid closed-loop technology is an option for people with type 1 diabetes who:
Have an HbA1c of 58 mmol/mol (7.5%) or more, or have disabling hypoglycaemia, despite best possible management with a pump, and/or real time CGM, and/or flash.
Are aged up to 18 years.
Are pregnant or planning a pregnancy.
If you think you might be eligible or you’d like to find out what’s possible in your geographical area, have a chat to your diabetes teams. There are 5 main licensed HCL systems available. Read on for a mini bio of each!
Pump: Tandem t:slim insulin pump
CGM: Dexcom G6 or G7
Licensed from: 4 years +
The pump is user-friendly with a chic touchscreen, and is pretty compact so can easily attach to clothes or go in pockets.
The system sets the target blood glucose level at 6.1mmols (110 mg/dL for my US friends!) Sadly this can’t be changed, which means the pump isn’t recommended during pregnancy as the target is technically too high for pregnancy, and can’t be manually adjusted to go lower.
People with type 1 can use different ‘Activity’ and ‘Sleep’ modes to fine-tune specific activities or times of the day, though if you’re going to use Activity mode for exercise, it’s wise to activate it 30 mins - 1 hr before the activity, to give the algorithm chance to work.
As a Tandem user myself, one of my bugbears is the amount of waste generated by site changes. The insulin reservoir isn’t brilliant, either, and my rep advised using a coin to flip out the old reservoir, which never feels that brilliant for such expensive and advanced tech.
Feedback from clients and myself is that this system works really well overnight, gently correcting any highs and preventing any lows. I’ve also found that when I’m hot on my carb counting and 15-min pre-bolus, the system can really shine.
2. CamAPS FX
Pump: DANA or Ypsomed
CGM: Dexcom G6 or Libre 3
Licensed from: 1 year +
Currently, this is the only system in the UK licensed for pregnancy. So shout-out to all my fertility crew, this one’s for you!
The default blood glucose target is 5.8mmols (104 mg/dL), but you can custom it between 4.4-11mmols (79-198 mg/dL). There are ‘Boost’ and ‘Ease off’ modes and a ‘Slowly absorbed meals’ function too, to help with fine-tuning. Overall, clients using this system tell me that their TIR is up and their A1c are lower, so it certainly works.
The system runs completely off an app on your smartphone, which will appeal to some as it means you can discretely bolus and not have to interact with the pump directly. No more fishing in your bra for your insulin pump (but also no shame if you do that. I do it all the time!).
Another key feature is that once you’ve entered your 5 day average total daily dose and weight, you won’t be using basals anymore so no more tweaking or tuning - which has its pros and cons.
This system only works off Android, so something to bear in mind.
3. Omnipod 5
Pump: Omnipod
CGM: Dexcom G6 or Libre 2+
Licensed from: 2 years +
The only tubeless pump to use HCL technology (an obvious advantage if wires aren’t your bag!). It means that in my opinion the pod changes are quicker - see point above about waste too, but it’s tricky to see if there are any air pockets in the pod - technically this shouldn’t be a problem if all air is removed during the pod filling process, but I am notoriously bad at getting those bubbly blighters out.
There are ‘Manual’, ‘Automated’ and ‘Activity’ modes to switch between. Feedback from the type 1 diabetes community is that the algorithm starts off fairly conservatively, but then gets more aggressive by pod 3-4. It learns steeply. Just hang in there as you get going.
Like the CamAPS FX you control everything from an app on your phone. The pod on your body is just a white box full of insulin, so once it’s put on, that’s it, no engagement with it necessary or possible. The algorithm is programmed in each pod you put on. The CGM data is sent directly to the pod to calculate how much insulin to give, so you don’t even need the controller near by for the algorithm to work.
But one downside is that you can’t see any history of insulin delivery, which some find frustrating.
P.S if you’re currently using this system and are looking for some top-notch tips for getting the most out of it, I’d really recommend this podcast series from Juicebox.
4. Medtronic 670G
Pump: Medtronic
CGM: Guardian 3 sensors
Licensed from: 7 years +
This was the first HCL pump introduced to the market back in 2016. It’s another great tubed pump option that uses Guardian sensors for the CGM part (so no integration with Dexcom or Libre). It’s also completely waterproof so can be used in the shower or the pool.
It has two modes: 1) ‘Smartguard auto’ mode, which automatically adjusts your basal (background) insulin every five minutes based on your CGM readings, and 2) ‘Suspend before low’, which stops insulin up to 30 minutes before reaching your preset low limits.
Users like the Medtronic pumps for their colourful, visual displays that are easy to work with.
Some downsides - user feedback is that the algorithm can take a long-ish time to learn from your body - up to 2 weeks to prevent post-meal spikes. And the CGM sensors require finger pricks for calibration. Boo.
5. Medtronic 780G
Pump: Medtronic
CGM: Guardian 4 sensors
Licensed from: 7 years +
This updated model requires far fewer finger prick calibrations (hoorah, I hear you cry!) and, like it’s older brother, uses SmartGuard technology (auto mode) and manual mode.
From work with my clients, I hear that the SmartGuard tech struggles to keep up with specific situations, like periods. And once you’re in SmartGuard, you can’t manually alter the basals, so you may have to switch between auto and manual modes a fair bit.
But the biggest issue for most t1ds seems to be around the sensors. The application process is a bit fiddly, and the accuracy can be poor, with users having to change the sensors more frequently than the 6-day wear period.
This system can integrate with Apple smart watches which is a useful perk if that’s your jam.
You’re able to set a temporary sensor glucose target of 8.3 mmols (150 mg/dl) for times where you’d need less insulin i.e. exercise.
Another plus for the two Medtronic systems is that t1ds really rate their customer service - it’s global and the company ship replacements worldwide efficiently without hassle. Especially comforting as we’re pretty familiar with the pump law of sod, which states that if anything should to go wrong, it will most likely happen when one is away from home.
And there ya go
The Beth Edwards Nutrition take on 5 HCL systems that are currently availability to some t1ds on the NHS.
It’s clear that all the algorithms improve numbers, and improve quality of life, but there are some niggles and downsides to each system which are useful consider if you’ve been offered a choice of system.
Do you use HCL? Any points you’d add? Let me know in the comments.