#408 Defining Diabetes: Insulin Sensitivity Factor

November 18, 2020Scott Benner

Scott and Jenny Smith define diabetes terms

In this Defining Diabetes episode, Scott and Jenny explain insulin sensitivity factor (ISF)—or correction factor—which is how many points one unit of insulin will drop your blood glucose level. They discuss how the ISF is initially determined, that it does not necessarily remain the same throughout the day, and the importance of considering modifications to the ISF value for hormonal or other changes along with other setting changes.

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DISCLAIMER: This text is the output of AI based transcribing from an audio recording. Although the transcription is largely accurate, in some cases it is incomplete or inaccurate due to inaudible passages or transcription errors and should not be treated as an authoritative record. Nothing that you read here constitutes advice medical or otherwise. Always consult with a healthcare professional before making changes to a healthcare plan.

Scott Benner 0:11
Hello, everyone and welcome to Episode 408 of the Juicebox Podcast. Today's show is the defining diabetes episode, Jenny Smith and I are going to talk about insulin sensitivity factor, also known as correction factor. This episode is part of the defining diabetes series. Actually at the very beginning of this, I'll go through all of the other definitions that Jenny and I have done together. But you can go find them in your podcast player. Please remember while you're listening that nothing you hear on the Juicebox Podcast should be considered advice, medical or otherwise. Please always consult a physician before making any changes to your health care plan, or becoming bold with insulin. My friend Jenny Smith has had Type One Diabetes since she was a child I think for over 31 years now. Jenny holds a bachelor's degree in human nutrition and biology from the University of Wisconsin. She's a registered and licensed dietitian, a certified diabetes educator and a certified trainer and most makes and models of insulin pumps and continuous glucose monitoring systems. There are very few people I asked Type One Diabetes questions of Jenny is at the top of that list.

The Juicebox Podcast is sponsored by the dexcom g six continuous glucose monitor the Contour Next One blood glucose meter, the Omni pod tubeless insulin pump, g Volk hypo pen and touched by type one. You can find out more about all the sponsors right there in the show notes of your podcast player. Or Juicebox podcast.com.

Jennifer Smith, CDE 1:52
My cat might come in visit here cool.

Scott Benner 1:55
Oh, how come we've never seen your cat before?

Jennifer Smith, CDE 1:58
Do you want to see my kitty cat?

Scott Benner 1:59
her or him?

Jennifer Smith, CDE 2:02
It's this one's a girl. We've got to two this is Lucille Ball buster. I don't know if you're a fan of Arrested Development.

Scott Benner 2:11
I know the show very well. That's where the names

Jennifer Smith, CDE 2:14
muster. One of our license plates is go bias and the other one is on young.

Scott Benner 2:22
We've already done a lot we have we've done laughs ready we've done Bolus timing range. bazel honeymooning standard deviation noncompliant algorithm extended Bolus Pre-Bolus Trust will happen glycemic load and index stop the arrows insulin resistance and over Bolus brittle diabetes low before high ketones bumping nudge rage, bolus compression loads and interstitial fluid. Oh my gosh, we've been doing this a long time. fat and protein rise feeding insulin dawn phenomenon feed on floor and the smokey effect. So that was the last one we did. Yeah, we did feed on floor Smokey and Dawn phenomenon like kind of all at the same time. So good question, what is left? I think more than I thought, actually, because I get to watch people talk about it online. I keep getting notes from people who say that these, like I think of the the defining diabetes series is like this nice little like addition to the show. For a lot of newly diagnosed people. They start with that, because they're getting so many terms thrown at them. They don't know what they are. So there's some that I'm gonna admit, I don't completely get all the time. Like I know how to use them in practice, but not theory. So I want to start with insulin sensitivity factor. Oh, that's a good one. But I want to I want to talk about it. Like, in every way, like how do people think of it MDI pumping algorithm?

Unknown Speaker 3:46
Okay,

Scott Benner 3:46
yeah. Okay. Yeah, I don't know anything about this. So so if I come into your eye, if a person gets diagnosed, and they show up in the, in your, your office, and you're like, Okay, here's what we're gonna do, we're going to set your insulin sensitive sensitivity factor at how do you get to that number? What is it and why is it?

Jennifer Smith, CDE 4:04
Yeah, I mean insulin sensitivity factor, and to clarify for some, like both on Omni pod as well as on tandem in the pump. Now it is called correction factor. Okay. So if you want to think about that, I think it's a little bit more, it's a little clearer what the term kind of implies insulin sensitivity factor correction factor, they're essentially both the same. What it means is, how many points or how many milligrams per deciliter, or if you're using millimoles, the same. one unit of insulin will adjust your blood sugar down by so let's say right now you started at a blood sugar of 180 and your ISF or insulin sensitivity factor it's at and you wanted to get your blood sugar to a target of 100 unit will drop you at points to get you to 100

Scott Benner 4:59
Okay, So it's so I think of it as correction factor. I guess, interestingly enough, yeah. Okay. But in honesty, if my blood sugar is, by the way, I have this like, I'm just doing that theory I go if my and then people are like you don't have diabetes, like I know If a person's blood sugar is 180 in your scenario, and you want to get it to 100, your correction, you know, your correction factors, you know, one unit per 80, obviously, a unit should move to 100. But

Jennifer Smith, CDE 5:29
should is the right, well, what

Scott Benner 5:31
if my blood sugar's 280? Now the same correction factor isn't going to work the same way.

Jennifer Smith, CDE 5:39
Often, what most people find is that over about a blood sugar of 250, which is also where your pump starts reminding you if you are a pumper, and or even if you're using MDI, you're often told if your blood sugar's above 250, check your ketones, right? So above that 250 Mark, it seems we kind of get like this sticky momentum of insulin, it doesn't quite work as it does when your blood sugar is high, but not yet. 250 or above. So it's a good question, because a lot of people get really, really irritated. I'm taking what I usually take, and last night at work totally fine. And last night, my blood sugar got high and it didn't work at all. Well, I mean, outside of any other variable to consider, let's say it's truly just the same scenario. Maybe blood sugar one night was 189. And the next night it was 297. Yeah. Right. So it does take a little bit more insulin to move your blood sugar. When it's higher than that about 250 mark. And I think something else in the picture there is you have to consider the deficit of insulin and maybe how long that deficit has been going on, like how much is really missing? Yes, one unit, again, in our example, should move your blood sugar by 80 points. But if you've been sitting at a 250, plus blood sugar for several hours, you're at a pretty significant deficit of insulin, almost like a glucose toxic setting, if you will. And so it's gonna take a little bit more insulin as well, as we've talked about it before. I think we had either part of an episode or whatnot all about hydration. I think it was in the CGM one, right. So hydration is key there too. So if you're not moving stuff around, your insulin isn't going to circulate or get moved and get it working as well as it should either.

Scott Benner 7:33
So isn't it is an insulin sensitivity or correction factor? is first of all, it's a it's a guess more than anything, right? Like you try it like the doctor sets it up for you it works or doesn't they turn it up or down? So it's a guest to begin with, that you dial in over time? That really is a measurement when there are no other influences impacting.

Jennifer Smith, CDE 7:59
That's an Yeah, in a roundabout way. Yes. I mean, the doctor does use a formula to give you a starting place for that insulin sensitivity factor. Most doctor use, they use what's called the 1800 rule, I'm sure you've probably heard of that before. essentially take your baseline insulin, your basal insulin, and you add that dose to the amount of bolus insulin you use on average for a couple of days. And then you divide that number into 1800. And that is supposed to give you a relative idea of what your sensitivity to insulin is, or will be, meaning one unit should drop you about this many points. So let's say your ISF is 60. You divide that into 1800. Right? So 30 is that kind of outcome?

Scott Benner 8:48
I like my way better.

Jennifer Smith, CDE 8:53
I kind of your way is sort of like it's adding precision to it. Right. And I think it also adds into and you've had Kenny on quite a bit, right? Yeah. And he does a lot with ISF right and it correctly too, because really if you look at ISF a lot of people also have one ISF that runs midnight to midnight they use the same darn number all day long. Now I can tell you from personal that does not fit the bill. I have several ISF that run through the course of the day dependent on what I've seen in that time of day when I've only corrected blood sugar again without like multiple variables in the picture. And I know that this works here and this works better here. So while the math of 1800 rule figures out to one stable number, right, that's not gonna really hit it.

Scott Benner 9:50
Yeah. I to me to the the setting of it. Setting up of it is take so much time because of the processor and like see the doctor They'll look at some stuff. Three months later, if you're lucky, we'll adjust it again. You know, it's just that feels untenable, the distance of time. And the way I think of it is like, try this, see what happens, then just move it until it's right and then stop. And I know that's, I don't know why that's scary for people. I'm not like, I'm not saying like, hey, the doctor said, you know, you're one to 50. Try one to one. You know, I'm not saying go crazy. Like I'm saying, you know, if he says one to 50, and you're like, that's not working, make it 145 and see what happens, then you know, and keep going. But you brought Kenny up, who comes on to talk about algorithm pumping a lot. And he's actually going to record with me next month, again. But so when you're using it in a in an algorithm, like in a loop or something like that, Mm hmm. I think ardens right now is like one to 43 I think one unit moves are about 43. And it can move around. It does be perfectly honest, now that Arden's getting older, I can tell you artists, three different people with diabetes every month, she's the she's the having her period person, she's the about to have her period person here. And she's the oscillating person, like there's three different like people she is. And her insulin sensitivity moves from about 42 to 45, or 46, depending on which week Brin and all I do is watch a trend, if she starts trending up and make her sensitivity stronger. If she starts trending down, I take it back a little bit. That's pretty much it, you know, and, and move her bazel a little bit in that time as well. usually pretty commiserate with the insulin sensitivity, the insulin says, yep, you know, it's getting stronger, the base is getting stronger, or vice versa.

Jennifer Smith, CDE 11:51
I think one other thing to comment on that, too, is as you bring up like the doctor adjustments, it's that ISF I've seen over and over is one of the pieces of insulin dosing that gets adjusted the least with the least frequency. Hmm. Most people play with their bezels, often kind of incorrectly because they're not quite sure what's wrong. They know that they need more, but they just add it in one place that they can think of to do at first, okay. And then they may play with their insulin to carb ratio. And ISF is sort of like the last thought. And unfortunately, like you just mentioned, if bezels are going up, because it's that time of the month, likely the other factors need to be adjusted along with that, because there's a resistance factor there that if you only dial in a bazel adjustment, yeah, it's not really gonna hit the need across the board. Well,

Scott Benner 12:50
so you're making me feel like that's how I see people end up with these bezels that are, it's funny, people's bezels are either way too weak, and they over compensate with their meal insulin and they bounced around, or their payables are way too strong. And they're like, Oh, my insert my food, I barely use anything. It's because like, it's because if they were to skip a meal, they dropped that because their bazel is so strong, right? That is, that is interesting, isn't it? Okay. All right, I can

Jennifer Smith, CDE 13:17
tell you kind of along the same lines as I have, and have for a long time, it was kind of like a peeve of mine. Honestly, in tandems pump, you can have a bazel profile that dials in not only the bazel, but also the insulin to carb and the ISF that work with that bazel profile. So all you have to do is enable that profile. And now you've got the insulin to carbon, the sensitivity factor that work with it. So like for a woman with her period or whatnot, you figured out that you need an insulin to carb of eight instead of 10. Great that's in the profile, you need an ISF of something like 40 versus 50, that's in the profile. So all you do is enable it and turns on. The other pumps don't do that you physically have to even though if you might have figured out you need more bazel for that time period, you might enable it. But if you haven't changed your insulin to carb, or your sensitivity factor, which you physically have to manually go in, have remembered or made a note of obeah I remember I used an eight last month and that worked a heck of a lot better than a 10. Right? Well, now I have to change it every single month. I have to change it.

Scott Benner 14:22
Yeah. Now listen, having it, it would definitely profiles are important. I think they really are to get them set up so that you can jump from one to another more seamlessly because I lose track sometimes too. You know, sometimes I'm like, what was it 43 or 42 last time this happened or, you know, but at the same time, like I I move everything together, like I think of it is like if I'm gonna send a soldier and I send them all in, you know, it's it's charged not You go first and we'll see what happens like and that way, by the way, you don't have to send as many, you know, so you just a great example, a little more Bolus a little more bazel. A little more factor. Everybody just turned it up a little bit, you know, and how far I don't know, like people would need to play with it for themselves to figure it out, but right, okay. And what I do notice, well, you know what I'm gonna I'll bring this up, I'll bring it up with Kenny because I am going to let Kenny like go on and really discuss his ideas about you know, one basal rate and then you know, working off of that, which like you said doesn't Yeah, it doesn't work for you and it doesn't work for Arden. Exactly. But I think for younger people it works. It can work really well. Better. Yeah, I just I'm I I definitely believe in that. What I said a minute ago that people get their bezels jacked up so high, they think they don't need anything for food. They don't realize that they're just there carpet bombing their entire 24 hours with bazel It's way too much. All right, thank you. You can check out the Dexcom g six continuous glucose monitor@dexcom.com Ford slash juice box. Get a free no obligation demo of the Omni pod tubeless insulin pump at my Omni pod.com Ford slash juice box. Learn more about the Contour Next One blood glucose meter at Contour Next one.com Ford slash juice box. Don't forget to check out g Vogue glucagon.com forward slash juice box. And of course touched by type one.org. Support the sponsors support the show. Jenny Smith works at integrated diabetes. And you can find out more about what she does at integrated diabetes.com. Thank you so much for listening. If you hold on one more second, I have just a couple more things to say.

If you'd like to hear more from Jenny and myself on management of type one diabetes, you should check out the pro tip episodes they begin at Episode 210 in your podcast player, where you can find every one of them at diabetes pro tip.com. Same thing about these defining diabetes episodes just search in your podcast player for defining diabetes. You have a great doctor, or would you like to share one with someone else? juicebox docs.com is an ever growing list of diabetes medical professionals that have been sent in by listeners just like you. Thank you so much for listening to the Juicebox Podcast. There will be another episode this week. I hope you're

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