CGMs and driving

While what you say is absolutely true, i.e. diabetics have driven without CGM’s, it is also true according to a couple of studies from the early 2000’s that Type 1 diabetics (as opposed to Type 2 on insulin who have the same rate of moving violations and accidents as non-diabetics) have double the rate of moving violations and accidents due primarily to hypoglycemic episodes.

It isn’t a huge stretch to make this argument to an insurance reviewer on an appeal, especially if the person was hypoglycemic unaware. Just because Type 1’s have been driving without CGM’s doesn’t mean that there is not room for improvement. Especially if the patient desires it.


If it could be shown that CGM usage results in reducing the risk of Type 1’s getting moving violations and motor vehicle accidents, I would support reduced insurance rates for Type 1’s that use them. I am personally not one who believes you should mandate or legislate things like this. I think people take risks in life and should own their decisions.

1 Like

Clearly this has never been shown, and even if it was shown, it could be for myriad reasons (maybe the people who wear CGM religiously are inherently more risk-averse and drive only Priuses).

Or maybe the reverse would be shown - i.e. playing with a CGM while driving might be found to increase the accident rate by increasing the level of distracted driving which is already exploding with all the digital devices people carry around as it is. So maybe CGM wearers should pay a higher auto insurance rate?

I think it is best to not adjust rates or mandate or legislate this at all, and instead do what you stated that I do agree with: people should be allowed to make their own decisions, and they should own those decisions.

(As a side note, I think your data about relative accident rates is inaccurate based on later studies:

As this paper points out, the latest studies suggest that there is a 12-19% increase in accident rate for T1 diabetics. And on the other hand there is a 4200% increased accident rate for 16 year old boys. So if we really want to keep the streets safe …

1 Like

Would you support higher insurance rates for Asian drivers if it could be shown that they’re involved in more accidents? That’s a rhetorical question… but kinda illustrates the point I hope.

I will absolutely stand by my point and in fact will further refine what I am saying.

It is safer for a person who is taking insulin to operate a motor vehicle with a reliable CGM.


We very much do not want to adopt the practices of whatever it is that most T1’s do.

I have great sympathy and enormous respect for Endocrinologists who have to deal with the public at large. I have no idea how they do it day after day after day.

We strive for better.


in some cases that is certainly true, I don’t think anyone is in a place to speak for all other people using insulin… I think that’s a good discussion between patients, parents, and doctors… not a good baseline for public policy.


Maybe the fact that they’re wearing a cgm proves that their diabetes is so wildly out of control that their license should be preemptively revoked---- a well controlled diabetic certainly wouldn’t need a cgm, why would they?

We all just have to be careful what we wish for, there are opposite sides of the coin to every aspect of this stuff

1 Like

I totally agree with you Sam and Jag. I think I said above, that I don’t think this should be legislated, and that if the data supported it, insurance companies should be free to adjust their risk profile. My personal view is that the government should step away from most of these decisions. With that said, I have lived in nanny states that took away someones drivers license for having an unexplained syncopal event and prosecuted physicians if they don’t report. I much prefer the non-governmental solution. Also, my son will be wearing a CGM or he won’t be driving my car.

1 Like

I don’t think you could possibly know this without studying it. I said it half in jest before, but I do think there is a possibility that someone tied to reading numbers off of their CGM could end up being distracted from their driving at a critical time. Let’s say I get a 150, and that’s too high so I want to tweak my pump basal rate up, and that gets me not just glancing at my screen but checking my recent history and then pulling out my pump which involves another screen and going through five button presses, and then checking both screens again to be sure everything is working, then … Or maybe I get no signal on my GCM, and I am uncomfortable driving without that data, so I try to figure out why the transmitter isn’t sending, which involves …,

Being unlimited doesn’t necessarily require more and more technology. For some it will, and if that gives more freedom from the minute to minute management slog that we all go through then that is great. But sometimes unlimited means using less not more technology, and relying more on your own experience and sensory inputs.

I am with @Chris.

I think that one factor is that those of us who had diabetes for a long time without CGMs often had better hypo awareness both because we had to be sensitized to those symptoms and because we probably weren’t in such tight control, so symptoms were stronger. It’s really surprising to me how many kids here are described as having poor hypo awareness, and sometimes I wonder if that’s a (possibly worthwhile) side effect of CGM use. I would definitely not recommend someone used to relying on a CGM drive without one, nor someone driving with poor hypo awareness drive without one unless they tested beforehand and stopped to do regularly during longer drives. I’m not sure that those are comparable situations though to someone driving without a CGM who is both used to functioning without one and has good hypo awareness.

1 Like

I think one of the downsides to relying so much on a CGM is that it makes people less able to identify things themselves. It removes some of the awareness you develop when not using it.

I have made it a point to continue making a BG guess before every BG test or every glance at the CGM. This is very helpful.

Many years ago I had so many of my friend’s phone numbers memorized. Technology has made that skill less important now. But what if I am stuck somewhere in an emergency without my cell phone? Then I am screwed. Same with the CGM for many people.

I read a thread somewhere about someone complaining about the 2 hour Dexcom startup, and how difficult it was to go 2 hours without their CGM (it was an adult PWD, not a parent with a young one, which is different). If you can’t go 2 hours without a CGM, you got problems.


As I was reading through everyone’s thoughts on the subject, it occurred to me that the experience of using an accurate CGM regularly is does come with attenuation. Which I then looked up, to make sure I was using the word correctly in my head, and I found this:

Which made me laugh, because of course it’s a reduction in The Force – that’s what Eric was trying to say, and he was totally right. :wink:

I still think the CGM is very valuable, and it just changes the way you can look at the diabetes – so I understand why people desire them.


I thought the opposite was true: that long duration of diabetes, and the subsequent repeated exposure to low BG, impairs how the body releases stress hormones, and we become less sensitive to symptoms. This is certainly what I continue to experience. Before my CGM, in the past couple of decades I was often astonished how low I could go (to the LOW reading on the meter) and feel perfectly normal. (In fact this hypo unawareness was the main reason I was encouraged to get a CGM, only this year, and it’s been a figurative if not literal life saver.)

In theory the CGM might reverse that: reducing the incidence of lows has been shown to restore symptoms to some degree. Again, in my experience, I’m sensing this is true: now that my CGM warns me at 4.4 (80) to take action, if I ignore it for a little while, I’ll start to feel that good ol’ shakiness coming on – long, long before the LOW point.

People who use CGMs right out of the starting gate may be less able to identify things (lows) because they so rarely or even never experience them. With a CGM, you’re much less likely to find yourself soaking wet and as good as brain dead.

But you can still have dropping BG. You can learn to sense those. You can learn to sense high BG.

The problem is when people look at their CGM, and either take food or insulin and don’t process the reason they are there.

That’s where the thinking comes in. What do I think I am right now? Why? What reasons are there for my BG to be high / low / good / rising / falling/ flat? Without processing everything, without thinking about how you feel - if you just read-and-react to the CGM - you are limiting your skills.


I guess what I mean is that most of us pre-CGMs aimed for a higher range—I’m always surprised to hear people with teens targeting not to be over 100 say. If you run a bit higher on the whole, lows feel subjectively lower. I agree that if that comes with more and more severe lows though, you are at greater risk of eventually losing awareness.


I agree with this a lot—starting at age 10, I grew up training myself to be hyperaware of my internal states as a diabetic. I realized as a young adult, it was part of why I tended to find using pot not enjoyable, because it would shift all of that in a way that was so noticeably off to me that it just felt awkwardly and palpably out of whack to someone so used to constant self-monitoring. It’s also made me much more sensitive to other effects and changes in my body as well, which is sometimes handy and sometimes annoying.


I agree absolutely.


I think there’s also a difference between hypoglycemic unawareness and hypoglycemic tolerance
I’ve alsways known quite well when I cross the 70 threshold as I feel different - but it’s never bothered me until I got down to 40 or less before I got the shakes and the intermittent blindness and stuff and it was much lower before I passed out
Even with the cgm I can still guess before looking if I’m below 70
Something strange happened yesterday though - I hit 70 and felt it and cgm confirmed it had slowly been dropping (I had 75 low alarm switched off) - by the time I got to Duane Reade to get some skittles I was already getting th blindness and shakes and I had only dropped to 65 / it was quite unnerving to have it happen that quickly and I have no idea why