Super Boluses... what are they? Do you use them? Is there any drawback?

Type 1 & LADA
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I read about these 15 years ago… It was the first book I had received about diabetes, I had absolutely no idea what it was talking about, so I skimmed, dismissed, and proceeded to deny that I had diabetes for some years to come. (It wasn’t 100% denial, but it turns out 89% can be just as bad).

15 years later, I’ve got my head in this book trying to understand all of these numbers, and I’ve just come across the “super bolus” again. This time, it seems very on point, ingenuitive. It sounds great, and I’d like to give it a shot, but then I realize it sounds dangerously close to one of auto mode’s moves that I’m so disapproving of… the withholding of insulin directly following a food bolus. So now I’m here, surrounding myself with smart people, trying to get some clarification and to hear about personal experience. I’ll try to water all that smart, good stuff down first by summing up what I think I understand, and telling you auto mode’s version of it… Then I’ll just sit back and prepare to learn.

What I think it is: in a nutshell, it’s frontloading insulin. It’s calculating what basal you would be receiving over the next… I don’t know this part… unknown amount of time and adding it to your food bolus. Then, and this would be an important part, it’s stopping your basal for that predetermined amount of time.

What auto mode does: When you give yourself a food bolus, in general, auto mode suspends all micro boluses for, again I’m not sure, a certain amount of time. It’s very frustrating to watch, but I also had no concept of the super bolus before. What I don’t know, because I haven’t tested it, is whether or not auto mode is including in that food bolus the anticipated basal delivery… and as soon as I say that, my guess is no. That’s the deal with auto, there is no fixed “basal”, so I don’t believe it could be. Can’t rule it out either. I can only say auto stops micro boluses, sometimes for a fairly significant amount of time, as soon as I get a food bolus, and I’m wondering if maybe it’s not as bad as I thought as it resembles a well-known strategy. I should add, however, it does it almost every time you eat so grazers would, in theory, see a more pockets of this.

Now that I’ve thoroughly watered it all down, I’ll put it in front of you with this: What do you know about super boluses? Do you use them? Are there any special considerations in how you use them? And what are the drawbacks?

And if your answer includes, wow, why don’t you try reading something on this side of 1975 because what is a super bolus? I wouldn’t be surprised. I don’t have to be smart in front of you guys… I come here to get smarter. :smiley:

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I used to do this for almost every meal. It can be very effective, but the drawbacks are that if it turns out you don’t need more insulin up front for a meal you will drop very low, and suspending the basal tends to cause more spikes later on or at the next meal since there is less insulin on board. Overall it started to cause me more problems and headache than it was worth, but I think it’s a great strategy for eating very high GI foods or even quicker corrections.

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There a lot of things that could be discussed on this topic, and many points that are brought into the whole thing.

But to start with - very simply - a super-bolus can have some benefit. But there can be some drawbacks, as you have noticed when your basal gets screwed with a bit.

So here is where it takes a bit of tangential discussion to get the whole picture. And I will go outside of your topic a bit, but there is a point to it.

Below is very basic stuff, which most everyone already knows. But I want to show it visually to lay the groundwork.

This is normal, old-school basal insulin here:

image

This is bolus insulin:
image

And this is your pump, using many little bits of bolus insulin to pretend it is basal:

image

And here is what happens when a pump using bolus insulin stops it for a while:

image

The illustrations are exaggerated of course, but just trying to make a point.

Okay, so you asked about super-boluses - “Do you use them?”. Not the same way. I do it a bit differently. And it has to do with the pharmacokinetics of insulin and how food is absorbed. And I can explain my ideas on all that if you want.

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I was hoping you’d appear… yes, please. :slightly_smiling_face:

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My answer is very much related to the question asked here:
very-basic-insulin-using-question

So, @kpanda01, please join us here!

I want to use very simple numbers to make it easy to illustrate. And we will just use the food and insulin as perfectly balanced to make it easy to show the principle.

So this is fantasy land, where all the numbers line up, okay? (Just like your endo or CDE thinks it works. :slight_smile: )

Let’s imagine your IC (or ICR or whatever the medtronics call it) is 1:15.

Suppose you are 85 and you want to eat 30 grams.

Simple math says that is 2 units. It would be perfect, right? Exactly 2 units for 30 grams.

And let’s say your insulin duration is 4 hours.

So yes, 2 units will make your 30 gram meal go away perfectly. You started at 85, and the 2 units and 30 grams will perfectly cancel each other out, right?

But when? When do you get back to 85?

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I’m intrigued, because i haven’t been able to figure out WHEN I’m supposed to be back at where I started. With easy to count meals,I do often find that I’m back where i started after about 2 hours or so. But if the insulin keeps working after it’s peak and is still going in hours 3 and 4, in theory I’d be dropping lower than where i started over time.

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Right, so as you know the insulin doesn’t always line up perfectly with the food metabolism.

In the fantasy land example - if your insulin duration was 4 hours, and if the carbs and insulin:carb ratio lined up perfectly, and all the food you ate was finished metabolizing in 4 hours - you would end up right where you started, with a BG of 85. But you wouldn’t get back to 85 until 4 hours after you took the bolus.

An insulin duration of 4 hours means it takes all of that time - 4 full hours - for every part of the bolus to be completely used.

Does that all make sense so far?

Because it gets a bit more complicated when we start to look at pharmacokinetics and the super-bolus…

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Certain professionals will tell you that you just have to find your carb ratio and you’ll be fine, but this is nonsense. Everything you eat digests differently, and many things have a combination of fast and slow acting carbs meaning one dose of insulin, no matter when it is taken, cannot account for all of the carbs perfectly. Then there are other variables including how much of your insulin is destroyed by your immune system upon injection, how fast it absorbs, your current activity and stress levels, how your favourite sports team is doing, etc. The best approach is to use a CGM and make changes based on your real-time trend, or eat very low to no carb using Regular insulin for the protein (but that’s no fun and I can never sustain it for long).

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I’m reading in bits… I’m taking it all in, 2.5 minutes at a time. Later tonight I plan on giving it full attention. Then I’ll unleash the full frenzy of questions and bad jokes… and, yes, I do understand… so far.

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Good, because it’s gonna get super complicated!
Ha, not really. :grinning:

When you get all of this down, the next thing to talk about is t-1/2. Insulin half-life.

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Well, either you have the same stubborn hang ups I do, or these are valid complaints. I don’t know which would be better.

That’s it right there. That’s the big one. It sounds like a fascinating idea… for the occasional indulgement but maybe not for everything all of the time. Just out of curiosity, would your current blood sugar have any effect on your decision to hold back the basal? And please don’t judge me here on my example, but if you had a blood sugar of a 200 already and were going to do a food bolus, would you still suspend your basal the same way if you were a 120 and doing it?

Trying to sort out which of my concerns are logical and which are just old ingrained misconceptions…

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We call a “super bolus” any extra bolus insulin up front that we have to give Liam for a food that we know he spikes badly after eating. Some foods (such as cereals) just require a large amount more insulin than other foods so; instead of depriving him of these things, we just double (or triple/quadruple if required) the amount of insulin he gets up front so that he doesn’t spike to HIGH and stay there for hours.

That’s what it is to us…but I know that term, like “micro bolus” has different, and specific, definitions for systems like the 670g.

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I started out using superboluses all over the place because they often gave a nice post-meal flatline, but, like others have said, they also often led to problems with lows or spikes down the line.

These days I use them periodically, like @ClaudnDaye, for foods I know will spike me – white rice, breakfast cereal, waffles with maple syrup, banana bread.

I do find them very effective for attacking stubborn highs, because if I reduce the following basal by 25% or 50%, I can dose more than I safely could if I were injecting the extra on top of a static injected basal. This gives me the additional insulin to tackle the high right now (or in an hour, Humalog-time) but not so much extra that I’ll seriously crash later on.

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Continuing with my illustration of super-bolus things.

Okay, so in fantasy land, this person starts with a BG of 85, has a 1:15 IC ratio, has an insulin duration of 4 hours, and he takes 2.0 units for 30 grams of carbs. And to add one more element, let’s say his food always metabolizes completely in 1 hour.

His numbers work perfectly. From the numbers above, you can see that an IC of 1:15 and 30 grams would be matched exactly with 2.0 units. His BG rises, but after 4 hours when all of the insulin has come in, he is back down to 85.

But…how do we get rid of the rise before the 4 hours is up?

First of all, insulin does not deplete linearly. It is not a straight line. Most all of the pumps use a straight-line formula for IOB (except for Tandem, I think). But it does NOT deplete in a straight line!

In reality, if you look at some of the pages for the pharmacokinetics of insulin, it is a general ballpark that 1/2 of the insulin you take is gone in the first hour (variations of course for depth of injection, absorption, exercise, yada, yada).

Here is one reference. Lilly has a bunch on their pages too.
(BTW, the reference to “Regular human insulin” is the old-school R insulin, not the insulin a non-diabetic makes :grinning:)

Elimination
When Humalog is given subcutaneously, its t1/2 is shorter than that of Regular human insulin (1 versus 1.5 hours, respectively). When given intravenously, Humalog and Regular human insulin show identical dose–dependent elimination, with a t1/2 of 26 and 52 minutes at 0.1 U/kg and 0.2 U/kg, respectively.
Rapid-Acting Analogues - GlobalRPH

(totally random unrelated tangent side-note - intravenous insulin has a half-life of 10 minutes, baby!
https://www.diapedia.org/management/81040961114/regular-human-insulin)

Okay, so using the example above, suppose our example person wants to get rid of that spike.

Half of his insulin is used after 1 hour (half-life I mentioned), and the rest of it takes 3 hours.

In the example, he is eating 30 grams and it takes 1 hour for his food to metabolize.

What if he takes 4.0 units for his meal instead of 2.0 units?

Half of that 4.0 units would be used in the first hour. 1/2 of 4.0 is 2.0 units, and that means in the first hour he has 2.0 units that got used. He ate 30 grams (which took an hour to metabolize) and he has a 1:15 IC ratio.

The 2 units that got used in the first hour (half-life of 4.0 units he took) completely knocked out that 30 grams. No spike!

Yea!

Okay, let’s prevent that with something. :thinking:
Any ideas, Smart FUD Reader?

So the super-bolus just borrows some insulin from the future and uses it for now. Kind of like using a credit card.

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none of the best solutions are… :slight_smile:

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and then suspend the basal?? I have learned to just go with “a bunch of extra” insulin before eating something stupid (and, yes, that’s the measurement), but I’ve never suspended anything. Yes, micro bolus does mean something completely different, but I wasn’t asking about that… I was trying to focus on things that might actually help. :smiley:

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I think this is a good place to start.

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No I never suspend the ball during these times. Needing extra insulin means everything is needed.

Micro bolus also help. :stuck_out_tongue:. We sometimes use super boluses in conjunction with micro boluses if the super bolus isn’t enough. :wink:

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And what’s your micro bolus size range?? How would you use them?? If you dont mind my asking…

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If I super bolus for a food that I know spikes badly and then, after he eats I see him go over 250 double arrows up, I’ll bump him more (micro bolus)… Usually 5 carbs worth at a time (.30) until he goes single arrow and levels out.

I’m not afraid of him dropping low at all during the day. We pay attention and just correct early enough on the way back down to stop the lows.

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