Non-invasive CGM. What could it really allow?

We’ve all seen the headlines about Apple and Samsung watches containing non-invasive CGM, and hearing the stories of what this means for those with and without diabetes.

But let’s think about this for a moment. What does it really allow?

Type 1 Diabetes

Starting with Type 1, what does Glucose Monitoring in your watch really look like? Well you can bet that it will come with an overload of warnings and disclaimers:

  • Do not use for medical purposes;
  • Do not use for dosing decisions;
  • Use fingerpricks if using for any medical decision;
  • This is not a medical device;
  • Think of anything else you possibly can to disclaim use of this device with diabetes.

Neither Apple nor Samsung will want to take on liability for poor data producing hospitalisation, and I wonder whether their current reticence to release these devices is technology or legally driven (or a combination of both).

I can imagine the lawyers being very uncomfortable about releasing a product that those with diabetes might be tempted to use to dose insulin, without a level of accuracy that might be considered “safe”.

Assuming this hurdle is overcome, where does this leave us?

For the first time, anyone who can afford to buy a smartwatch will have the opportunity to monitor glucose levels. Let that sink in for a moment, and think about what it means.

There’s a perspective that suggests that, once again, those who are unable to afford these things will not have access to this technology. But let’s think about that statement for a moment. Many phone companies offer watches as part of the 24 month subscription that phones tend to be bought with. Instead of having an additional £159 per month to pay for CGM (if you can’t get Dexcom on the NHS) you now might get it for an extra £20 per month as part of your phone plan. That’s quite a different view of the world and for many will be seen as much more affordable.

And what about use?

If you use any Bluetooth based system, you are already aware that without a phone nearby or in water, you have no way of telling what glucose levels are. Will the systems being planned by Samsung and Apple allow for use when swimming, for example? For both athletes and parents that is likely to be a game changer. Having said this, the options currently available all appear to use optics, and there’s no telling how that might be affected by water. It’s something you’d expect to be though…

Of course the other thing it potentially opens up, assuming that the data is good enough, is the integration of Automated Insulin Delivery systems onto your watch. With a downtime for charging.

Now all you need is a small pump, and your watch. No need for a phone or phone like device. While it sounds quite amazing, I think it’s likely to be a long way off.

Type 2 Diabetes

If, all of a sudden, smartwatches are monitoring glucose levels, then it provides an instant change in what those with type 2 learn about themselves. Their body’s reaction to food and drink. What exercise does. Absolutely everything. Now you’d be able to, on a personal basis, determine individual treatment plans based on actual data for what happens to individuals with each treatment. That could enable a spectacular population wide study that provided a far better epidemiological view of treatment for type 2 than anything that has been achieved so far.

It would require individuals to sign up and give permission for data to be accessed but given the lack of CGM use and the outcome of the studies that show CGM use in type 2 where insulin is used is better with CGM than without, widening this population to those who don’t use insulin, and appropriate training on what to look out for, potentially, again at an epidemiological level, could generate hugely important outcomes and information for future diagnoses.

Those without diabetes?

And what of those without diabetes? There’s been much commentary on social media and in the press about the use of CGM amongst those who don’t need it for clinical reasons.

Stepping away from the rights and wrongs associated with that, once the information is available anyway, without needing to apply a Dexcom or Libre, those arguments become irrelevant. At this point the systems and apps that are tracking this data constantly serve two purposes.

  1. Providing the ability to understand (on an athletic level) how fuelling and glucose levels drive both physical and mental performance levels. Imagine the overlay of food, glucose level data, sleep data and something like Garmin’s body battery data and all of a sudden you’re getting a more wholistic view of how fuelling affects you.
  2. Medium term tracking and alerting of individual propensity to problems with the glucose metabolism. With the tracking working on the phone and able to spot patterns, such as slow post prandial return to euglycaemia or higher long term levels, there’s a potential to catch those at risk of type 2 earlier.

While these may be helpful, I can also understand how some may not particularly want the types of identification in bullet 2. Again, something that would need to be subject to an individual’s choice. The downside of this is in areas where insurance drives healthcare. Its not impossible to see insurance companies demanding access to CGM data and adjusting premiums accordingly, to the detriment of many. It presents an unpleasant picture of the attitude that many organisations in this world have.

What can we conclude?

Watch based CGM functionality potentially creates a mechanism to democratise access to glucose data, but at the same time, in areas where there is an insurance based healthcare, to squeeze many in the pocket, and potentially out of insurance.

At this stage, I think the benefits outweigh the risks, but there is potential for misuse and the growth of the medical hack industry around this information.

For those with long term conditions who may benefit from cost reductions with more data, I don’t think there’s too much of a downside, but I think care will be required around interoperability and use of that data.

Ultimately, wide access to glucose data will become “yet another piece of health tracking” and people will cease to blink an eyelid at it. Whilst it remains novel, it attracts a lot of attention, but once the novelty wanes, it will become an everyday item that people use to make decisions.

But that’s a fair way off just yet…


  1. This may be one feature that brings awareness to those that don’t realize they have diabetes.

  2. Good to hear that an android is being included in this type of CGM. Now the big question, since I’m a noninsured working Canadian with no insurance/help for gadgets like this, is the cost. For myself as well, accuracy is important (in my dreams I’d be able to afford the Dexcom G6). It’s funny though, that after growing up with test tubes and urine, for knowing how well the insulin was doing it’s job … 56 years later … even without all these gadgets … I’m doing pretty good … but dang fingers are getting calloused from the vampire machine (so much for my job as a smooth finger tipped masseuse.

  3. I have to say that I am very cynical about then Supersapiens project.
    Metabolism is a complex beast and involves far more than just glucose.
    Clearly CGM has been a fantastic addition to diabetes care, allowing the review of data and the earlier opportunity to correct glucose to “normal”. For those without diabetes they already have a system for doing this – it’s called homeostasis. CGM in that case allows observation of one point of data and how it responds to fuel going in and being used – and as expected there will be small variations.
    Supersapiens – or supercynical pseudoscience ? A non-evidential base for use of CGM in people without diabetes !

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