Can't find numbers beneath Control IQ

I just got a Tslim X2 and am using Control IQ in sleep mode 24/7. (Tandem calls us “Sleeping Beauties” a term I am not particularly fond of but it shows that there seem to be a decent number of people who are not happy with their high standard range). My target is 70, well below even their sleep mode and so I want to fool the system by increasing my basal by the same percentage that they reduce it when I am between 70 and 110.
I have been googling for what that percentage is but I haven’t been able to find it. Lots of info about WHEN they make the change. Just no info about HOW MUCH of a change they make.

  1. Can anybody point me to that number?
  2. Does anybody have any thoughts on staying in MY range instead of theirs?

Go to pump, history, basal, today?.

Proprietary info I’m afraid. You can calibrate your Dexcom to be higher which will keep you where you want to be. A few people do that. The system is going to consistently cut off or reduce your basal when you are below 110 so increasing your basal probably won’t do what you are trying to do. Also if you want to stay around 70 the pump is going to constantly be beeping at you.

If you adjust your ratios carb and correction factor. Do it in small increments but aiming for z70 as your baseline . The algorithm will almost totally correction factor and I tell my pump I weigh more than I do cut offat not likely it will be able to do that. I got my overnights to be aroundd 95 by adjusting my weight that I tell my pump and my cf

Thank you for your reply, Timothy! I am experimenting in sleep mode which offers no correction bolus. The tradeoff is that it targets a lower band - 110-119. I feel like I will be better off in this mode if I can’t pay attention. It is essentially acting like looping and only affecting the basal, but it will jump in at 119 instead of 160. It may turn out that I would be better off allowing the correction boluses but they wouldn’t happen until 160 and I want insulin upped long before I get there (and hopefully don’t.)

Hi, Firenza. thank you for your reply! Yes, I ended up calling and they were going to connect me with engineering to talk about it but I found out enough. The guy told me about the status button where I could see the current bolus as I played with it which was great for me. (I didn’t know about that.)
I was going to say that calibrating DexCom incorrectly sounds like a bad idea because you don’t know where you are but I thought about it and love the idea. The reports will be way off but it’s the A1C that counts. I am thinking it will take days to recalibrate though. My last sensor was reading extremely low and it kept rejecting my calibrations. It took 36 hours to finally get close and I even tried cheating at one point, saying my level was higher than it was. I like the idea if I can do it. I’ll probably stay in sleep mode, though, because of the narrower band. Now I’m rethinking all of this. I think I will stay on my path and If I can’t get it to work, I will look at recalibrating. I think that if I increase my basal by the right amount, I’ll be in good shape, but I like having the recalibration as another thing to try. Thank you and I’m sorry for all the thinking out loud.

I’m curious - given that you want to fool Control IQ so radically, why use it at all?


I get it. Wanting the convenience of auto adjusting, but with a lower target!

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Exactly, Mr. YoungHeart.

Hi. I tried the sleeping beauty approach - but found that the variability in my basal level made it really difficult to bolus correctly for the next meal. I am one of those people who does best with a lot of basal on board before eating. That being said, a high basal drops me during the day so the sleep option felt like a great tool to prevent me from going low.
Right now, I use it only at night. I have increased my weight by 125 lbs and do run a higher basal at night. It’s not perfect but most days I wake around 100 which feels fine to me.

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Hi, Barbara. I am in the same boat regarding leaning on a high basal. I upped my basal by quite a bit but I’m still hanging higher than I would like (100ish). I am going to keep increasing my basal to try to force me down and then see what happens when I don’t eat. (I am hoping that the basal will get shutoff in time when it expects me to drop below 70l We’ll see.

The Control IQ algorithm will start reducing basal delivery below 112 mg/dL and shuts it off at 70mg/dL. It might seem reasonable to assume it is a linear reduction function based solely on glucose level - BUT it isn’t.

It is dynamic, non-linear in response to rate of decline and it has a reaction time. And it can’t reduce basal to a negative value if it learns from your CGM that you dropped lower than 70 in the last 5 minutes. If you set the range to 60mg/dL to suppress nuisance alarms so you can sleep, you may drop too low for them to be timely warnings.

There are too many variables to routinely intentionally overdose (higher basal) at night to get a stable level lower than 112mg/dL Raise it and it will reduce it faster, but maybe too late to oprevent overdose. Regardless of the basal rate number you use it won’t work to keep you stable at 70mg/dL.

If you had a good handle on your basal profile, and great control you could just disable Control IQ at night. But if your control was that good, why do you need a loop pump’s automation?

The question I think you should consider, is why do you want your nightime level to be at 70mg/dl, the lower boundary of what endocrinologists consider to be reasonable for a conscious insulin dependent PWD?

Without Control IQ, is your TIR greater than 95% and your average CGM reading below 126 with no time below 70mg/dL? If so, you haven’t needed Control IQ - so far.

And what if you come home exhausted or become sick from the flu or an infection, drink or take a medication that helps you sleep while your BG drops lower than 70mg/dL? Will you remember to reengage the Control-IQ safety system?

Control IQ like every FDA approved semi-automated system, is designed to protect you from hypoglymia when sleeping - to watch over you when you are least able to protect yourself. least able to make fast, good, effective decisions.

The Control IQ sleep mode target range corresponds to an A1C of 5.5 to 5.8. That straddles the boundary between “normal” and pre-diabetic.

Only you can decide whether the value of your life is such that risking it to get a lower average BG at night is worth it.

btw, The A1c test is basically a useless metric for someone using Control IQ and having a TIR greater than 90%. It’s accuracy is +/- 0.5 . Your average CGM level for 30 days and SD are better measures if you want to see the effect of lifestyle modifications,.


Thank you for commenting, pstud123. I have been playing with with Control IQ and have now gotten it to protect me from dangerous lows. I am in sleep mode all the time and I recently had a worst case of insulin resistance driving me very high (270), followed by the post-crash sudden drop. The shutoff of basal happened early and I leveled off right at the low end of MY range, which was the 60’s. I am extremely happy with that. I am not as happy with the high end compensation because sleep mode turns off automatic correction boluses but I can take some time figuring that occasional problem out. While I do agree that TIR may be important and A1C may not be important for you, it is just the opposite for me. The “range” they use is not my range. We all need to deal with this in our own ways and I like that you have something that works for you. If we were able to set our own ranges and adjust when basal cuts in and out, that would be fabulous. I know looping allows that but there is a significant hell month to go through before they let you in. I’m trying to work with Control IQ and so far, I have the most dangerous piece working perfectly. I just need to bring my occasional highs down and push a little further to get my resting level stabilized lower than the 80’s - 90’s and I’ll be happy. Thank you for the discussion and suggestions.

Having a different target is different than having a different range. Your target may be higher than mine or the pumps’ but should still be somewhere within that same range, and your time below range and far below, should be no worse.

That you rely on CIQ for hypo protection suggests that your night basal rate and/or bedtime glucose levels aren’t right yet, or possibly you are being overreactive to compression-caused alarms. Having a personal target of 60, and a simultaneous a problem with persistent highs suggests that your glucose variability, your ICR, CF and your ability to respond manually to prevent and correct highs, (especially persistent highs) , which is what you must do in sleep mode for highs, need improvement.

In short, you as a system/process aren’t stable. Without a stable process as a foundation, tight management of anything to reach specific goals is difficult at best. Without relevant metrics, management to reach an arbitrary number is impossible.

Aside from A1c being an average that doesn’t indicate hyper- or hypoglycemia, why or when it happens, calibrated A1c tests have an “accuracy” of +/-0.5.

When I was last tested, my CGM weekly reports going back 90 days showed I was consistently having an average weekly glucose level around 126 mg/dL with a SD of 20 or less. The A1cNow test said 5.3. That’s like an average BG of 105 mg.dL - normal.

There’s NFW that A1cNow test was accurate! A1c does not indicate quality of control AND it is not an accurate or a dependable number that you or any doctor, can use to make rational decisions about what changes you should make. A doctor who tries to without analyzing available CGM data is undereducated, out of date and not following ADA/AACE/international best practices. With 75% of all PWD not reaching the high A1c targets, the A1c "gold standard’ isn’t gold for therapy. It’s a measure of the effectiveness of medicine, that effective therapy is not being prescribed and universally afforable.

My personal target is reaching a goal I can measure day by day, achieve and maintain. I have a long range goal of getting my glucose under good enough control that I can bring my average down safely, with no time below 70 mg/dL. That corresponds to an A1C close to or below the diagnostic criteria for diabetes and lower than my endocrinologist feels comfortable with. I use response patterns and daily and weekly CGM and BGM statistics, not A1c, to tell me how I’m doing continously, inform my decisions and keep me safe.

To do this safely, I needed to get good enough control that I won’t be dependent on pump automation most of the time. Instead it will be like level 2 automation to warn me when unexpected things happen.

But I recognized that this is a complex project not a simple one, and with the tools that I have the most effective approach I can take is to address problems one at a time starting with the most potentially dangerous and serious, and use what the pump does as data to refine my management technique.

As an engineer I believe that trying to override a relatively stupid but complex algorithm makes less sense than modifying the process it tries to control. So Im using experiments to get good metrics and minimum lifestyle modifications to get the results I need.

When I started using a pump in April 2022 my first objective was protecting from night time lows.
This is when I’m most vulnerable. For most of my adult life my sleep quality was terrible because I was afraid of hypoglycemia.

So I started with a t:slim and Basal IQ and counterintuitively raised my personal lower range limit to 75mg/dL I then completely eliminated nocturnal hypoglycemia by determining my basal profile systematically using the pump in “manual” mode, doing tests to recalculate my ICR and CF making a very minor adjustment to my diet.

Then I upgraded to Control IQ. While it did keep my night time glucose level higher than before it’s not an immediate concern because I was still having drops from pre-meal boluses and high peaks after meals.

I tackled the peaks by adding fiber and reducing carbs from one meal at a time. This reduced my TAR to 2 percent. Then I experimented with extended boluses to flatten the curve and eliminate rides that required Control IQ to intervene. Finally I’ve started lowering the curve.

Imo It’s more important to flatten and lower the curve to an always good level than to try for near-near normal levels part of the time, especially when that is my time of greatest hazard…

I’m very close to where I want to be .
This was my last seven days:

And all day yesterday (2300-2300,).

I still have work to do, dinner Is a complex problem to be cracked unless I forego variety, but now it’s easier.

I use Xdrip+ for monitoring because it’s able to give me much finer and multiple indications as well as a much much better display than Dexcom or Tandems screens plus better analysis tools for seeing near real time effects.

I don’t know that it’s possible for anyone else to successfully use the exact approach I’ve taken but I believe that it’s usable with some modification for you to get to a good stable safe plateau before seeking a lower safe target than mine.

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