Relying on CGM for hypo awareness while driving

[Swimmer]

I am type 1 LADA and have just had my driving licence revoked on the first 3 year renewal application. When it became apparent I was getting little in the way of hypo awareness symptoms, I was completely honest with my medical team and asked for a CGM and got one and no-one told me I wasn't allowed to rely on it for driving, so having my licence revoked has come as a bit of shock. I wouldn't mind if I thought I was unsafe, but I think having a continuous display of BG every 5 mins in the car, with alarms, makes me safer than most. I think the DVLA should recognise that modern technology is revolutionising type 1 management and work up rules around CGM use in the car. Does anyone else have any experience of this?

 

[Lucyr]

I was completely honest with my medical team and asked for a CGM and got one and no-one told me I wasn't allowed to rely on it for driving, so having my licence revoked has come as a bit of shock

It’s your responsibility to educate yourself on the DVLA requirements not your teams. You should have informed DVLA when your hypo symptoms reduced and had the licence revoked then rather than waiting till renewal. Technology isn’t 100% reliable, so I agree with the DVLA position on this. Work on getting hypo awareness back, then you can reapply.

 

[Inka]

Welcome @Swimmer 🙂 As Lucy says, it’s not a good idea to rely on tech for a number of reasons. How long have you had Type 1/LADA? It might well be possible to regain your hypo awareness with the right support.

 

[Lucyr]

Here’s the relevant parts of the DVLA information on hypoglycaemia awareness and driving, running your blood sugar higher and preventing any hypos for a period of time will hopefully help restore your hypo unawareness. In the meantime you can use the dvla declined letter to apply for a disabled bus pass.

https://assets.publishing.service.gov.uk/media/5d8b92dc40f0b6098d33fefe/inf294-a-guide-to-insulin-treated-diabetes-and-driving.pdf

 

[rebrascora]

Hi and welcome from me too.

Really sorry to hear you have had your licence revoked and I really hope we can help you to regain it. In some respects I agree with you about DVLA with regard to CGM as even those of us with good hypo awareness can have fluctuations in that awareness and to be honest I have a feeling that using CGM may well erode hypo awareness for people in the future as they rely solely on CGM and don't learn to recognise their early hypo warning signs, just like none diabetic people mostly don't know when their levels drop below 4.

I also get a bit frustrated with the lack of clear definition of "hypo awareness" because it seems to me it is a bit of a sliding scale and a number of factors can be involved. Firstly, how do you know that you lack hypo awareness? Have you blacked out from a hypo before you were aware you were going low? If not, how low do you go before you can feel it and which meter do you use and have you tried different meters to confirm that the meter you are using is reliable. CGM is not reliable for assessing hypo awareness in my opinion. Losing your right to drive is a big issue but equally it is important to keep the general public safe (including you) and a car is a potentially lethal weapon. I personally feel there should be a better way of assessing hypo awareness because I think people don't have a clear or accurate way of measuring it.

For instance, the BG meter you use can have an impact. I mostly use a Caresens meter (my official meter) along side a Freestyle Libre CGM. For me Libre fairly consistently reads 1mmol lower than my finger prick BG especially when my levels are dropping, so Libre can show me as being 3.4 and I am actually 4.4 according to the CareSens. I tend to feel hypo signs between about 3.8 and 4.2 on the CareSens meter. It can be dependent on whether my levels are dropping fast or more gently. A couple of years ago I bought some Optium test strips to use in my Libre reader and what I found is that the Optium test strips often read very slightly lower than the Libre sensor and therefore even lower than my CareSens,.... I have 2 CareSens meters and they tend to agree with each other with regard to consistently reading higher than Libre. My gut feeling is that Libre and the Optium strips both read lower than my actual BG and the fact that my Libre HbA1c prediction is always several points lower than my actual HbA1c sort of confirms that. My Caresens are my official BG meters, and we are advised to accept that reading over Libre so I go by that, but what if I was officially prescribed Optium test strips? Would that then mean that I didn't have such good hypo awareness and I should not be driving? I think it is also important to bear in mind that BG meters can have a 15% error margin, so at that hypo level there is still quite a bit of variation which could make a significant difference to our perception of our hypo awareness. I personally don't think whether we drive or not should come down to which meter we use, but potentially it could from my own experience with those Optium test strips and Libre.
I really think there should be some better way of quantifying hypo awareness and I do sympathise with your situation.

We have had a number of newly diagnosed people on the forum, saying they have no hypo awareness, but unless they have become unconscious before they were aware they were hypo then I have difficulty understanding how they accurately assess this.

 

[Satan’s little helper]

I am type 1 LADA and have just had my driving licence revoked on the first 3 year renewal application. When it became apparent I was getting little in the way of hypo awareness symptoms, I was completely honest with my medical team and asked for a CGM and got one and no-one told me I wasn't allowed to rely on it for driving, so having my licence revoked has come as a bit of shock. I wouldn't mind if I thought I was unsafe, but I think having a continuous display of BG every 5 mins in the car, with alarms, makes me safer than most. I think the DVLA should recognise that modern technology is revolutionising type 1 management and work up rules around CGM use in the car. Does anyone else have any experience of this?

Hello, I’m sorry to read this. What I know is the DVLA only take the box ticking of “yes I feel the classic symptoms when hypo.” DVLA does accept CGMs are common. However, they do need to be satisfied as part of the fitness to drive that you know the low signs. CGMs or the connection to the device can fail. I test & keep my meter handy the same way I would observe other definitions of safety whilst driving. That’s not to say I don’t have the early warning set up too. I just don’t mention it to DVLA. Working closely with your team & regaining hypo awareness. You might only have had your licence revoked for a year?

 

[helli]

I am with the dvla on this.
Relying entirely on tech (which can fail) to determine if you are safe to drive is not safe. I believe it is very important to maintain hypo awareness without a CGM,
I would also question whether having a display that updates while you are drive could be potentially distracting. I am not sure the legal position - reading a sat nav is ok but reading text messages whilst driving is not.

 

[rebrascora]

We do however also rely on many many aspects of technology to keep us and everyone else, safe whilst driving. The whole car is a mass of technology and bits of it can and do fail. Nothing is risk proof. Brakes can fail, a tyre can blow, people with no known heart disease can have a heart attack or stroke.
As you say, how is looking at a BG display any different to looking at a sat nav or looking at the clock.... particularly if you are running late. Who calculates and assesses the risk on these things. What about someone who has a cold or hayfever and is more likely to sneeze frequently whilst driving. These all pose a risk or distraction but are not legislated. None of it is clear cut, but I really think the lack of a clearly defined standardized way of assessing hypo (un)awareness and what people understand by it, is the place to start.

 

[CliffH]

We do however also rely on many many aspects of technology to keep us and everyone else, safe whilst driving. The whole car is a mass of technology and bits of it can and do fail. Nothing is risk proof. Brakes can fail, a tyre can blow, people with no known heart disease can have a heart attack or stroke.
As you say, how is looking at a BG display any different to looking at a sat nav or looking at the clock.... particularly if you are running late. Who calculates and assesses the risk on these things. What about someone who has a cold or hayfever and is more likely to sneeze frequently whilst driving. These all pose a risk or distraction but are not legislated. None of it is clear cut, but I really think the lack of a clearly defined standardized way of assessing hypo (un)awareness and what people understand by it, is the place to start.

I think I'm probably a safer driver now that I have to check my blood sugar level every two hours when I'm driving than before I developed diabetes - when I'm sure I was sometimes below 4.0 (such as when driving back from a cycle race without having eaten anything) without knowing it and without realising that it was a safety issue.

I agree with you that it's not safe for the DVLA to rely on people having a shared understanding of what hypo (un)awareness is - and for people being honest about it with them.

 

[Satan’s little helper]

I would put this forward; there are many warning lights in the average vehicle dial pod that could be observed while checking your speed. (As you should.) some are safety features like ABS tire pressure air bag warnings. (Though tire’s tread should be checked at interval during a physical “circle check.” Along with running light bulbs.) All warning lights investigation if they don’t go out when the ignition is on. Oil lights, brake lights if the handbrake is off. I even have a low coolant alarm. Warning bulbs can fail. Which is why there is a test sequence when starting the vehicle. All these are a driver’s responsibility. So I can understand utilising a CGM alarm as an early warning system so that the driver can pull over where safe to do so & investigate.

 

[CliffH]

Hello, I’m sorry to read this. What I know is the DVLA only take the box ticking of “yes I feel the classic symptoms when hypo.” DVLA does accept CGMs are common. However, they do need to be satisfied as part of the fitness to drive that you know the low signs. CGMs or the connection to the device can fail. I test & keep my meter handy the same way I would observe other definitions of safety whilst driving. That’s not to say I don’t have the early warning set up too. I just don’t mention it to DVLA. Working closely with your team & regaining hypo awareness. You might only have had your licence revoked for a year?

Presumably, even though it might be legal for one's readout to be visible on a mobile phone in a holder, it would be illegal to actually swipe a Libre disc with the phone (or any other form of meter) whilst driving? If so, there'd still be the need to stop completely every two hours to test.

 

[CliffH]

I would put this forward; there are many warning lights in the average vehicle dial pod that could be observed while checking your speed. (As you should.) some are safety features like ABS tire pressure air bag warnings. (Though tire’s tread should be checked at interval during a physical “circle check.” Along with running light bulbs.) All warning lights investigation if they don’t go out when the ignition is on. Oil lights, brake lights if the handbrake is off. I even have a low coolant alarm. Warning bulbs can fail. Which is why there is a test sequence when starting the vehicle. All these are a driver’s responsibility. So I can understand utilising a CGM alarm as an early warning system so that the driver can pull over where safe to do so & investigate.

Would that though fall foul of DVLA's exhortation shown above that we "must not actively use" CGMs whilst driving? It would be good to get DVLA's view on that.

 

[Satan’s little helper]

Would that though fall foul of DVLA's exhortation shown above that we "must not actively use" CGMs whilst driving? It would be good to get DVLA's view on that.

Nothing wrong with using a CGM. Just don't substitute it for a loss of hypo awareness. DVLA's view from their medical advisors seems clear to me, on the forms.

 

[CliffH]

Nothing wrong with using a CGM. Just don't substitute it for a loss of hypo awareness. DVLA's view from their medical advisors seems clear to me, on the forms.

My guess is that the "must not actively use" rule (and the word "must" suggests that it is a rule, rather than guidance) is about distraction whilst driving.

 

[Satan’s little helper]

My guess is that the "must not actively use" rule (and the word "must" suggests that it is a rule, rather than guidance) is about distraction whilst driving.

Just as long as it isn't in hand & toyed with whilst driving. Cited as "driving without due care & attention?" Regarding DVLA hypo awareness. Fitness to drive means you need to know the signs. A warning from a CGM, just don't cut it for them.

 

[helli]

Presumably, even though it might be legal for one's readout to be visible on a mobile phone in a holder, it would be illegal to actually swipe a Libre disc with the phone (or any other form of meter) whilst driving? If so, there'd still be the need to stop completely every two hours to test.

There is no need to swipe a Libre with a phone unless it loses signal.

 

[rebrascora]

So can we agree on what constitutes a hypo to start with? (ie under 4 or under 3.5?) I know you cannot drive if you test below 4 but does that mean you are technically hypo? or just that you should be starting to feel hypo warning signs at that level?) and at what point do you think you should be aware of it and what do you use to measure it (ie which BG meter?) and how can you be sure that is giving you reasonably reliable results?

At 15% error margin ....
3.9+/- 0.6 (15%) gives you anywhere from 3.3 - 4.5mmols and 3.4 +/- 0.5 (15%) gives 2.9 - 3.9mmols.
So if they consider a hypo is 3.9, do you need to be feeling it at or above 3.3mmols on your meter to consider that you have hypo awareness?
And if they consider 3.4 as a hypo, then a similar argument would suggest being able to feel it at 2.9mmols or above on your meter, means you have hypo awareness, which seems rather low for safety.... but maybe that depends on the meter?

I just really can't get my head around how you quantify "hypo awareness" and as @CliffH suggests, he probably did not have hypo awareness before he was diagnosed if you consider a hypo 3.9 or below, as many non diabetics similarly would not.

I believe I have good hypo awareness because mostly I feel them between 3.8 and 4.2 on my CareSens BG meter but what if I didn't have that and instead I used Optium test strips in my Libre reader and they were showing my hypo awareness was between 2.8 and 3.2. I would not consider that good at all and yet from the occasional comparisons I have done, they would be comparable meter results. ie Optium reads about 1mmol lower than my Caresens.

 

[CliffH]

There is no need to swipe a Libre with a phone unless it loses signal.

Sorry, I'm not sure what you mean. If I want to get my current blood sugar on my Libre app, I have to swipe it with my phone - unless there's another way of doing it that I'm missing?

 

[CliffH]

So can we agree on what constitutes a hypo to start with? (ie under 4 or under 3.5?) I know you cannot drive if you test below 4 but does that mean you are technically hypo? or just that you should be starting to feel hypo warning signs at that level?) and at what point do you think you should be aware of it and what do you use to measure it (ie which BG meter?) and how can you be sure that is giving you reasonably reliable results?

At 15% error margin ....
3.9+/- 0.6 (15%) gives you anywhere from 3.3 - 4.5mmols and 3.4 +/- 0.5 (15%) gives 2.9 - 3.9mmols.
So if they consider a hypo is 3.9, do you need to be feeling it at or above 3.3mmols on your meter to consider that you have hypo awareness?
And if they consider 3.4 as a hypo, then a similar argument would suggest being able to feel it at 2.9mmols or above on your meter, means you have hypo awareness, which seems rather low for safety.... but maybe that depends on the meter?

I just really can't get my head around how you quantify "hypo awareness" and as @CliffH suggests, he probably did not have hypo awareness before he was diagnosed if you consider a hypo 3.9 or below, as many non diabetics similarly would not.

I believe I have good hypo awareness because mostly I feel them between 3.8 and 4.2 on my CareSens BG meter but what if I didn't have that and instead I used Optium test strips in my Libre reader and they were showing my hypo awareness was between 2.8 and 3.2. I would not consider that good at all and yet from the occasional comparisons I have done, they would be comparable meter results. ie Optium reads about 1mmol lower than my Caresens.

I can tell that I'm going low when my Libre's reading about 4.5 or less. Anything above 5.0 and I feel 'normal'. Of course there's a delay between what the Libre reading is and what my actual BS level is. I sometimes do long drives and I deliberately get my BS well above 5.0 before I start and then keep it above 5.0 with snacks (and no insulin!) when I'm checking it every two hours.

 

[rebrascora]

Sorry, I'm not sure what you mean. If I want to get my current blood sugar on my Libre app, I have to swipe it with my phone - unless there's another way of doing it that I'm missing?

Libre 2 works as a full CGM and sends updated readings to your phone automatically every few minutes, so you shouldn't need to scan unless you have a very old operating system?