Ideal a1c and "time in range"

Type 1 and LADA
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@roger5

It makes a difference what the definition of hypoglycemia is. Under a 7 A1c has nothing to do with hypoglycemia, otherwise almost every single person would be hypoglycemic since a “normal” averages around a 5.1 A1c.

CGM’s are the best tool we could have. It helps keep track of BG levels all day a lot easier. I have an A1c of 5.1% I stay in range with a TIR of 97% between 65-160. With around a 23 SD. (and a co efficient variation of 20.9)

This means I don’t have wild swings very often, and in fact the wildest upswing is from swimming, so I put up with it, DP or FOTF, which can be erratic so I have no choice, or a new sensor that loves to be wildly off when started, can be reading too low or too high. ( which is very irritating as it’s messing with my numbers for no valid reason!)

But the fact that we can keep track of our numbers better means we can aim for lower A1C’s a lot easier and stay safe. My doctor knows that I will be aiming for an A1c of under 5 one of these days and she has not said anything against it at all. She knows I keep track closely and have great control. She has said I have the flattest lines she’s ever seen.

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82

The more enlightened doctors evolved to this new perspective. In the last nine years, I have commented to a few endos that judging risk of severe hypoglycemia on an A1c level alone is short-sighted. Glucose variability, as measured by standard deviation and coefficient of variation, when low, permits a low average without undue hypo risk.

With one doctor in particular I felt that she had not considered that argument before. People with glucose profiles similar to mine are more common on this forum than in the typical doctor’s patient population. Their rush-to-judgment conclusion that a low A1c (let’s say < 6.0%) means undue hypo risk is right much more often than it is not.

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83

It’s hard to find studies that look at only Type 1’s, when looking its relationship to outcomes and mortality - and that use thresholds that we can use - but I went looking the other day, since @Marilyn6 had responded to one of my comments regarding 6-7% being an ideal range. This is one, but understanding that many are focused on variability more than average. Granted, there might be findings that contradict this, but I haven’t found them yet. Maybe someone can share any studies that point to better outcomes in newer patients that have both lower variability and lower (<6%) HbA1c,

HbA1c and Mortality

Glycemic control and all-cause mortality risk in type 1 diabetes patients: the EURODIAB prospective complications study - PubMed (nih.gov)

Variability and Outcomes

Long-term Glycemic Variability and Risk of Adverse Outcomes: A Systematic Review and Meta-analysis - PubMed (nih.gov)

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Note the limitations of the first study in the conclusions section:

“We recognize that these low HbA1c levels may be related to anemia, renal insufficiency, infection, or other factors not available in our database.”

I believe renal insufficiency causes a lower A1c than would be predicted using blood glucose values.

In the statistical analysis section, they state:

“Three knots were placed at the fifth, 50th, and 95th percentiles (HbA1c 5.6%, 8.1%, and 11.8%) ”

Which I believe indicates that approximately 5% of participants had an A1c below 5.6% which would be about 165 people out of 3,250. That’s actually a lot more people in that A1c category than most studies have.

The discussion section of the study states:

“Additional adjustment for nephropathy in our study indicated a stronger magnitude of the association for HbA1c below the reference, whereas the association for HbA1c greater than the reference was slightly attenuated. This could indicate that the positive association between low HbA1c and all-cause mortality risk might be stronger in those with nephropathy.”

Apparently they could adjust for nephropathy but not renal insufficiency.

It’s an interesting study.

I also found this part interesting:

“In our study, severe hypoglycemia events more often occurred in the lower compared with the higher HbA1c quintiles ( P for trend < 0001); however, additional adjustment for severe hypoglycemia events did not attenuate the association between low or high HbA1c with all-cause mortality. This adjustment was, however, limited to self-reported hypoglycemia events. Also, Gruden et al (30) did not find an association between severe hypoglycemia and cardiovascular events or an increase in the markers of inflammation and endothelial injury in the EURODIAB PCS.”

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85

Thank you for the detailed response, and I did understood the limitations before posting, but it’s a paucity of proof that I would like to end - if not for others, for myself - so if anyone has good studies please share them. I’ve seen many on Type 2s, but few of Type 1s.

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I guess I don’t really understand.

The ideal A1c and time in range is that which a person without diabetes would have.

There are reasons why that may not make sense for someone with diabetes - say they’re older and the person with diabetes may not be able to manage that well.

In my case, I would not be able to get my average bg lower without making diabetes much more intrusive in my life (e.g. creating a routine that would be unsustainable emotionally for me). Even with those routine changes, I’m not sure I could reduce my risk of severe hypoglycemia enough to obtain non-D numbers. Whatever changes I would make to get me to those non-D numbers would influence the longterm trajectory of my health. There are so many ways of managing diabetes and everyone seems to respond better or worse to different methods.

I don’t really see how a study could capture that minute of information in today’s world, and even if it did, very few people are getting that close to the non-D range anyway.

I’m still aware that the ideal numbers are the ones that a person without diabetes would have. I haven’t seen any evidence that convinces me otherwise. All evidence I have seen - and there is a lot of it - is that higher bg values and higher A1cs result in complications.

I don’t know why a “normal” A1c and “normal” numbers would not be the “ideal” for someone with diabetes. Its just that ideal isn’t always attainable.

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87

I just don’t understand why a diabetic with non diabetic A1c’s wouldn’t be healthier than a diabetic with diabetic A1c’s in the long run, as long as severe hypoglycemic events are non existent or very minimal. I think studies are difficult because we don’t know what condition the participants were in when the study started. I think that was the problem with the ACCORD study.

I have had non diabetic A1c’s for close to 18 yrs. At this point I am not sure how to have a much higher A1c. My kidneys are fine by the way.

If I didn’t have diabetes my A1c’s would be considered excellent.

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88

It’s my experience that most doctors are about 10 years behind the current understanding of all this glycemic control, what it means and what is the best course of action.
Unless you have a doctor who is focused on a large patient population of diabetics.
I find myself explaining a lot of things to my doctor, however the RNP in the same office is on top of it.

You can’t blame them, this stuff changes rapidly with technology and new studies and different approaches.
5 years from now we might realize we are wrong about a few things that we are doing now.

When I think back now what it was like 34 years ago when I was dx, it wasn’t in the 1950s medicine seemed rather modern.

However there was almost no data regarding tight control. Tight control wasn’t even possible because glucose testing was just starting.

89

I go by these guidelines, from this study

image

Essentially averaging 7.0 a1c “ish” or lower, watch your BP, hope your family members lived long, keep your kidneys healthy, weight on point, etc.

A 7.0 a1c vs 5.5 doesn’t seem to matter for longevity (and to be honest, even 7.5 is what they usually consider “intensive control)

That being said, my all time personal average is maybe a 7.0-7.2 ish, but have had years of 6.0-6.8 or even a sporadic 8 here and there.

I’m on a thyroid and preventative cholesterol pill but otherwise no complications, nearing on 25 years, which I know isn’t that long, but i’m hopeful…

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90

I like the chart below in the study you linked.

image

I agree that you get diminishing returns once you reach a certain level of glycemic control.

I find that I think more clearly and feel better when I’m around 80-100, and that my brain starts to feel fuzzy once I get above 150. So for me, there’s more than one reason for keeping my bg values in range.

However, this was less noticeable when my control wasn’t as good. As my control improved I noticed it more. I’ve wondered if getting older has also impacted how I feel, but I’m still pretty young (early 30s) so you wouldn’t think that I’d really feel it yet. Like you, I’ve had diabetes for 25 years.

Longevity isn’t the only thing that matters. I’m hoping to avoid retinopathy and neuropathy for as long as possible.

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91

20 years after onset used to be the life expectancy of a T1
So you already beat that.
Now it’s close to the average without diabetes.
However you can’t ignore a simple fact.
People with diabetes are forced to focus on what we eat, how much and when.
That generally means we make healthier food choices than the average person.
I have a non diabetic brother who eats like a frat boy.
He is a lot heavier than me and pays no attention to food or drink. I don’t know his cholesterol or other numbers.
But keeping on top of our intake is really key to all people, as diabetics we are kind of forced to.

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Another study shows that absent of kidney problems, t1 lifespan is near identical to the general population. For 20 years after. I think a follow up was done as well. There is one conflicting study that still shows a higher incidence id ischemic heart problems in diabetics impacting lifespan, but it is counteracted by lack of risk taking behavior in t1s, so it all averaged out in the stats. I prefer to focus on this one

In conclusion, our results demonstrate that in long-term follow-up, renal disease, including persistent microalbuminuria, is a key determinant of long-term excess mortality in type 1 diabetes, but that individuals with type 1 diabetes who avoid renal disease appear to achieve long-term mortality similar to, or only marginally higher, than seen in the general population.

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@JamesIgoe

Unfortunately I think these studies pay particular attention to A1c and not how they got that A1c? That was always the golden rule and really still is for most. And I still think it’s an important number. But it means for a bunch or some of the general population of T1’s a low A1c can mean low lows with highs to get to that level of A1c

CGM’s are gaining in popularity fast with a wealth of information coming with them. But the biggest movement is in the US. I believe a big drawback of the first study is it’s European. I say that because Europe has a lot lower percent of Type 1’s, while Scandinavia, UK and North America all have the highest rates. While a couple of countries supply Cgm’s to their Type 1’s, UK does, it still even only supplies a Libre to about 15% of Type 1’s. So you possibly have not as good care because of doctors being unfamiliar with type 1 in a lot of the European countries and then the fact that the lower A1c might mean lower numbers off setting higher numbers. (It is a problem getting care and information for type 1’s in some European countries.)And that might mean it’s completely almost irrelevant to a “healthy” well controlled lower A1c Type 1.

But this is where TIR and SD come into play as showing what is actually going on.

And as @katies87 pointed out this was self reporting hypoglycemia events. To me that means what?? Because at what levels were the hypoglycemia event an “event”? This can go towards the fact that they might be having severe lows that need help or bad enough to acknowledge, so how low were the “lows”? And that goes back to the fact that if you don’t have severe lows with a low A1c, does that even mean anything for you if you don’t .

And it does come down to what you are able or want to achieve. The only reason I have such great control is because of retirement for me. I could not have managed as well before retirement.

But a biggy seems to be, keep your kidneys healthy!

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94

Proof isn’t common sense, and none of this is meant to say that non-diabetic A1c is not ideal, but…

  • Sensible is not the same as a fact, or proof, or a study. I appreciate statistics and studies, and I wasn’t asking if it was sensible - that already seems obvious - I was asking if anyone had proof. If it was true, it should be easily and readily published.

  • How many times has something seemed sensible and was found to have a detrimental effect. The history of medicine is littered with treatments that seemed sensible but were useless, detrimental, or deadly. Often, the flaws in reasonable thinking don’t become obvious until studied at scale.

  • As an example, I had some minor tingling in a foot, and I mentioned that the touch test seems to be less sensitive on the same foot. My endocrinologist looked over my bloodwork and saw a low-normal B12, common in neuropathy. She prescribed a high dose of B-12, saying no one ever died from too much B-12. A few days later, while researching neuropathy and B-12, to see if it worked - I did not find any studies showing a reduction in neuropathy - I found a study showing that high B-12 supplementation led to higher mortality. I emailed her, and we reduced my dosage.

More

  • Blood pressure and the J-shaped curve - naturally occurring low blood pressure is healthy, treated BP that is lower than normal starts to increase mortality
  • HRT and increased cancer risk
  • Vitamin supplementation - often worthless, sometimes harmful, or even deadly
  • Type 2 and intensive management - in a major study it increased mortality
  • Diet prescriptions - low fat, or high carb

Sensible is a hypothesis, studies and meta-studies are validation.

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95

Yes, the null hypothesis would be: the ideal numbers for someone with diabetes are the non-D numbers.

If there is strong evidence in a study that contradicts that, then that would definitely be good information to know.

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96

Yes, if the data was available across a diabetic population, with adequate demographic and medical history to compensate, one would be able to look at correlations or at least differences between grouping, Non-D, D < 7, 7+, as well considering variability, for complications and mortality.

Now that hospitals are becoming the dominant care center, as opposed to individual practices, medical records are electronicized, and CGMs becoming commonplace, there is the possibility of better analysis and resulting care.

At the cancer center I work at, while data analysis was always important, it has become even more so, if not just for care, as a business imperative. With CGMs, I think that manufacturers, in addition to hospitals, would want to make a case for tighter control. As cynical as it sounds, it would be good for business.

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I hope so. My, admittedly limited, experience with hospitals has left a very negative impression on me. I have little confidence in their ability to track things on that kind of a level.

I agree that it would be helpful though.

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I started a thread some time ago asking people about their tech, and since I have much of my personal data going in into Google Fit, i.e., CGM, fitness/activity, weight/BF, and sleep, I paired that with some programming to do some analysis. Similarly, with so much data being collected, it should be easy to do some preliminary analysis at scale.

Although I found, and continue to find, some relationships between data points, nothing correlated with my glucose numbers.

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There have been some practices, often aligned with hospitals, that have provided great care, my experience with individual practices has been more often negative, and always less integrated. Although hospitals can seem a little cold, I generally prefer them, but that is a bit in the abstract, since in NYC, the density of hospitals and doctors can lead to better care, and they are often centers of excellence and highly integrated.

I have my blood work done here at NYU, and the system has easily accessed records going back years. My endocrinologists have been there, and it has a great hand surgery department - I might choose someone else for this, when it is needed - and since some aspects of my care are less critical, I also see a dermatologist there, as well as an internist, but still, great doctors. I did have a cardiologist that was external, but started using NYU’s, with the treadmill/scans done on site.

100

The reason I am staying with a non diabetic A1c and keeping the best TIR that I can manage, which is about 85% if nothing interferes with my care, is because I do not want to have a stroke or heart attack in the near future and I don’t want to develop diabetic neuropathy. From what I have read it can be quite horrible and I don’t want to deal with it in my later years. Right now I still have full feeling in my feet and no diabetic neuropathy. Of course, I don’t want all the other complications either. At 70 I am doing well for having had this disease since 1959.

I know very few people who have had diabetes for over 60 yrs like I have. Once in a while a few will make a comment or two here, but except for Richard who has lived many more years with diabetes than I have, I don’t know if anyone regularly posts. I would like to know how they made it this far and what complications they are experiencing and what advice they can give.

I know that Dr. Bernstein is a great example of living a long life with diabetes without too many complications and he certainly keeps a non diabetic A1c and stays as flat lined as possible. I wish that his woe worked for me.

The only person I knew a bit personally who had diabetes for longer than I have had it, died recently of a sudden heart attack at the age of 74. He was a pharmacist and well known in the diabetic world. He was one of the first pump users and a spokesman for living with diabetes. I have no idea what his A1c’s were like or his TIR. I don’t know what other complications he dealt with.

I will continue working hard at taking care of my diabetes, so that I can live as well as I can as long as I can. My only diabetic complication is heart stents and that is a major complication. I realize that a stroke or heart attack may be coming soon but I will do everything I can to keep that from happening. For me that is a non diabetic A1c and excellent time in range, a low fat mostly plant diet, and miles on my exercise bike. It is a heck of a lot of work, but I feel I am worth it. I don’t think at this point that a study is going to make much difference to me one way or the other. I feel that I am my own scientific study and so far what I am doing now is working. We will see what the future holds. Good luck to everyone.

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