Is a lower HbA1c always better?



In my case, as a grazer, running between 80 and 90 is ideal and actually means less severe lows. My frequent snacking is perfect to help keep my blood sugar up without needing a lot of insulin. If I do the same at a 130, I need to do insulin for those snacks. Roller coasters are where I experience terrible lows. I might stay on the lower end for a little too long while keeping a lower BG, but I don’t have those severe crashes as often.

And now I’ll go back to keeping quiet and just reading.


Yeah, I’m not saying to target a specific A1C either. I’m saying this: If you target a specific, safe, but on the low-end blood sugar and time in range and **ALSO ** time spent in hypoglycemia (I’m putting out the percent time low that my endo mentioned upon diagnosis) – and you actually meet the goal to spend a small amount of time in hypoglycemia how likely is it you will wind up with an A1C of 5.5?

My guess is that a person who is aiming for, say, a BG of 100 mg/DL AND aiming to spend less than 0.5% of their time below 55 mg/DL is very unlikely to wind up with an A1C of 5.5, for instance, if they actually meet the target of spending so little time critically low. This is *on average – not saying you in particular (I think you’re a person who maybe could pull it off – but I’m saying the average person.)

And then the second question, which I think is relevant, is this:
Okay, concede (for my sake) that the average Joe cannot realistically achieve both a very low percentage of time spent in hypoglycemia AND actually meet their target BG of, say, 90 or 100 mg/DL on average. Then, given the risks of both high and low BG, what is a reasonable next step? Should that person prioritize avoiding hypoglycemia, and therefore accept a tradeoff of some higher blood sugar (either by raising his target BG or by correcting less aggressively when high, waiting longer between corrections, or by treating impending lows at a higher BG – whatever it is – but focus mainly on removing the hypos?). Or does the evidence suggest he should just accept those lows and continue to target that lower BG number, even if it means the hypos stay? (And don’t say BOTH because I know that in theory that’s a great idea but in practice you have limited mental bandwidth and in my experience most people tend to focus on one, then the other, not both at the same time.)

In my mind, it makes more sense in that instance to raise the target, because I do think hypoglycemia is a valid concern. But I think others on here see hypoglycemia as NBD and therefore see it as “the cost of doing business” so to speak, and are willing to tolerate many lows a day in order to maintain more time spent closer to their target BG. While they are always trying to avoid lows, they are not necessarily changing their whole strategy to do so.

To me, that’s the heart of the argument about A1C, really; it’s about blood sugar management and how aggressively you should be aiming for normal. If the answer to the thread A1C question is “the lower the better” with no floor, then the answer to how aggressively you should aim for normal is “pretty darn aggressively.” If the answer to the A1C question is “there’s no added benefit below 6.5” then the answer is “as aggressively as I can within reason, but not so aggressively if I can’t avoid hypos” and if the answer to the A1C question is “it’s harmful to have a low A1C if the A1C is tied to hypos” then the answer should be “I really should not target normal BG very aggressively at all.”


@jag1, you are absolutely right.

Yes. Because it is the most likely explanation (or the most economical one in terms of hypotheses), it does not mean that it is the right one. It is possible that, in the future, we would find a causal relationship between time in hypo, or in severe hypo and CVD. Among all the channels it could take, I am a touch concerned, in particular, about the relationship between hypo and inflammation.

I agree with you here also.

Speaking for myself, I am not ready to dramatically optimize for less hypo time at the cost of average BG, but I am definitely more careful of hypo time and watchful of research developments.

I agree too. But I don’t think that this is a choice we have. We don’t optimize for A1c, but for average BG, and I believe that aiming for one level of BG or another slightly lower one makes practically no difference to the time in hypo. I will expand on that in a post below.


@TiaG, I disagree with your premise that aiming for a slightly higher or lower BG number impacts your time in hypo. I speak in these terms based on our experience with my son, first as a child (diagnosed at 11), then as a teenager.

Once my son was out of honeymoon, but before hitting puberty, life was good. Our time in range (TIR) was in the 90%. Our time in hypo was very low, practically inexistent. Our nights were flat. The bulk of our highs was due to poorly estimated meals, and they were very easy to correct, because they followed correction factors well. When we were diagnosed, we were aiming for 120. Within 6 months we started aiming for 100. Soon after that, while still aiming for 100 with a correction, we would always want to be below 100 once we were in range. We had no hypo problems altogether. When we got close to hypo it was always predictable and we could take some milk or sugar in time.

When we got to puberty, things changed radically. Our TIR went down to 50%, and our SD went from 25 to 50+. Our highs are almost all hormonal, and do not follow correction factors. We need to stack frequently, many times, to smack down some highs. Almost all of our hypo time is due to enormous corrections to try to get very strong hormonal highs down. This evening, for instance, we had a hormonal high that went up to 280 and did not react to normal dosing (by ratios). We ended up having to inject another 9.5 units AFTER having dosed it once already per CF. Then, to stave off likely very deep low, we had to eat a 40+ carb meal when still at 150 and coming down fast (about 15-20 per 5 minutes).

So you can imagine, I think, what the difference in aiming for 120 or for 100 (or between 130 and 90) would be for us. When we are far out of range for hormonal reasons, it does not matter a whit: the difference between the two is about 0.65 unit out of total insulin injected of about 15 units… If we don’t perfectly time and gauge our landing corrections (food), we’ll end up in a deep low for 1.5 hours, or we’ll rebound up badly.

So, for a kid in puberty similar to ours, and, I imagine, for many pre-menopausal women (since it seems from the threads we read on the forums that the two are remarkably similar in some ways), aiming for a little higher or a little lower makes practically no difference. Your choice is not between 5% (if you can get there) and 6%, it is more between 5% and 8%, because you would have to aim a lot higher (probably around 180) to be able to significantly impact hypos just because of the larger tolerance of a higher aiming level.

On the other hand, I do expect that, once our boy is out of puberty, he will be back into a much easier regime, where, again, there will be very little difference between aiming for 120 and 100.

But, beyond the fact that I believe, from our experience, your premise to be incorrect when looking at “aiming” for a BG level, I also feel that the theory that we “aim” for a BG level is too simpleminded to be effective.

In reality, it is totally possible to aim corrections at a higher level, then, when you are in range of a higher level, to adjust your goal to a lower one. This is what we do all the time: we try to come down to the higher end of the range (our range is 70 to 120, so that means 120 to us), then we glide down to below 100 if possible. So, when you use more complex management techniques, it does not make much sense to quantify your full approach into a single number, which, hypothetically, would be the BG you target.

So I think that your premise is incorrect in two respects: first because most of our time in hypo results from gigantic corrections for nasty hormonal peaks, where the “aim” makes no difference, and second because “aiming” at a number is a very small part of the techniques we use to control BG.

Beyond that, however, there is another element. As @Nickyghaleb wrote, it is a lot easier to correct when you are in range or close to range than when you are far out of control. So, to us, it works much better to do a severe correction at 130 (which may well bring you into hypo) than to correct more mildly, then have to deal with a resilient high at 250 or 300, where the hypo is almost guaranteed and much more likely to be very long.

In these circumstances, I simply don’t think that aiming at 100 or at 120 makes much of a difference. The concept of “aiming” for a BG (or worse, thinking that we can pick an A1c), in my opinion, is not one that is fruitful to understand what can be done to avoid hypos. I know that it is useless to us as a management tool. I feel that there is a pretty good chance you will feel the same when Samson grow to be the age of my son. But who knows :slight_smile:


So I think that your premise is incorrect in two respects: first because most of our time in hypo results from gigantic corrections for nasty hormonal peaks, where the “aim” makes no difference, and second because “aiming” at a number is a very small part of the techniques we use to control BG.

I actually don’t think that’s what I was saying: i I’m saying you can aim for lower hypos through a variety of means, including but not limited to: higher target BG, less aggressive use of corrections, less stacking, and correcting for lows at higher BGs. And what you have described actually confirms what I’m saying; normal BG management that the endo will tell you upon diagnosis is that you wait 3 hours after the last dose before you do a follow-up correction. That would mean, in your instance, that you guys are being very aggressive in aiming for normal blood sugar, by any standard, textbook endo’s definition. And the result, as you say yourself, is sometimes hypoglycemia. Who is to say that if you used old-school endo guidelines, rather than sugar surfing, for instance, that you would not be able to eliminate many of those hypos altogether? It’s very possible that you would. In the end, though, you’ve decided that hours and hours at 300 are not worth the tradeoff for a potential risk associated with a transient and easily-corrected hypo. (FWIW I agree with you and hammer highs in that range with Samson as well.)

Still, I do disagree somewhat that targeting a lower BG wouldn’t make any difference at all, though in general if your target is above 80 I don’t think it’s a *huge difference. What we’ve found for Samson is that he drops at a certain rate until he gets to about 100 mg/DL. Below that level, he drops much more quickly and is much more insulin sensitive. If you’re targeting an 80, for us, the difference between that 80 and a 50 could be less than 0.1 units; but the difference between 180 and 150 could be 0.2. I agree that when you’re slamming a high there’s a lot of “slop” in how much insulin you really need to get things moving in the right direction – but certainly there are edge cases where the difference between targeting 80 or 120 could cause one additional hypo. I know for sure with us, for instance, if we aim to nudge a 160 mg/DL at night down to 110 (Samson’s night-time target), we often get unpredictable results and he has crashed to 55 mg/DL. Whereas if we had a target of, say, 140, the pump would not recommend any insulin and he would not have crashed. So I can see, in my own experience of BG management, that there are some situations where lower targets do result in increased hypos. Whether it increases overall time in hypoglycemia over the month depends on how often those situation occurs. And for what it’s worth, Samson’s daytime target is 100 mg/DL – so that’s not super super low but I would imagine it’s considered “aggressive” by many endos.

And yes, your son is going through growth hormones. But I would imagine that the “smooth sailing” type of BG management that you described, with tight targets and minimal SD, where it’s possible to completely avoid hypoglycemia, and which only seems to really settle in for many people when they’re in their 20s, might actually apply to a minority of people; factor in the kids, the women still going through monthly cycling; those with other underlying health conditions that make BG management more erratic, and I can easily imagine MOST diabetics are dealing with a level of erratic BG management more akin to what you’re seeing now than what you were seeing earlier on.

But that’s just my two cents. I don’t disagree that it’s easier to correct when you’re in range, I don’t disagree that complex management techniques muddy the relationship between hypos and tight targets, or that hitting a high aggressively early on can sometimes lead to less of a prolonged hypo (or at least a less dangerous one that’s overnight, for instance) than letting it sit up there. But I am saying that if you take a population of average diabetics and change their target from 120 to 100 or 90, you will probably wind up with more hypoglycemia. I also would be absolutely, positively curious if anyone on here has achieved a sub-6 A1C without spending more than 2% of time low. People on here keep insisting that it’s totally, absolutely doable to get a really amazing A1C and NOT be low-carb and NOT face increased risk of hypos. I don’t mean it in a challenging or sarcastic way; it’s just I’ve never actually seen anyone with numbers like that who was not low-carb and if they are achieving such tight targets I would love to pick their brains. :slight_smile:


@jag1 Excellent point. To bring this into the reality of everyday diabetes treatment, my doctor specifically said that I should raise my A1c to about 6.4 from 5.5 solely to avoid critically low Bg levels.

I think he would be happiest if my A1c was 5.5 without any critical lows, but, in reality, that is an unreasonable expectation for a diabetic controlling Bg with exogenous insulin.

And thank you @Michel for that excellent summary.