1st A1C since starting on TandemX2 CIQ

Had my first endo appt, first A1C since starting on the Tandem pump. I thought it was going to have bumped up a few points, as I’ve struggled with post-prandial spikes and getting my settings dialed in. I usually run about 6.1-6.3 so I was expecting something on the high side of that range. Um, no.


I know A1C is not the be-all/end-all (my TIR was also good, like 97%). But that’s only the second time I’ve been below 6 in the 40 years I’ve had T1. So I’m pretty wowed. I think part of the credit goes to the T-Connect app, which gives me a pretty granular sense of when the pump isn’t doing what I want in terms of anticipating and correcting spikes, and the pump software is flexible enough to let me do things manually when I feel the need to be more proactive. Anyway, I’m pretty happy with this machine.


“when the pump isn’t doing what I want”

I had similar experience, and learned how to compensate. Since starting Tandem X2, A1C in mid 5s.

I use sleep mode 24x7.

I try to catch times the pump does reduced/0 basal, since most times I get a better results with treating pending lows with food/glucose.
If I pre-bolus, it may also start reducing basal, so will add more insulin to food bolus to compensate.

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You put your finger on one of the more annoying behaviors of Tandem and commercial AID algorithms. What’s the point of pre-bolusing if it’s going to set right to work dialing down the effect? I have considered just switching off CIQ for a bit when I’m doing that, but haven’t decided if there’s a downside I’m unaware of. And of course forgetting to switch it back on again.

Haven’t tried the 24/7 sleep mode dodge yet. One thing is that it will not do a correction bolus automatically for you, but given how often I end up doing them manually anyway that’s not such a big deal. Thinking about it…

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Been there, done that!!

But I keep T:connect on and nearby, so can get quick glance to remind me.

Not sure if everyone responds same way, but when I get insulin suspended, I can rise quickly, likely abundance of liver glucagon dump.

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I had the same complaint when I spoke with the Tandem CDE. Her suggestion was to prebolus using the extended bolus for only 20 minutes or so. It seems to help keep the pump from going into its insulin withholding mode.


I’ve had fairly good luck with Tandem CIQ, A1c has been in the high 5’s to low 6’s.
Pre-bolusing with the extended function has worked well to negate the algorithm’s stopping basal(I usually drop BG to ~4mmol/L(72) pre-meal)
I find most days that CIQ will make me hypoglycemic even with very low basal rate. Even if I walk my dog around the block I become very insulin sensitive. So most days I’m in manual mode until supper then I turn on sleep mode. About the only time I can run CIQ is if I’m at my computer or driving. My wife says the problem is I never sit still!!


When I remember to do this, it works well.

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When I allow my CiQ to just do its thing I also end up in the same range. 5.8-6.1. And I’m very happy to be here consistently. When I first moved to tandem and I felt like I had more data and I was doing corrections often on top of the algorithm, I actually got down to 4.9%. It was a lot of work and I was going low a few times a week, so I decided to accept high 5.x and I have to say it’s pretty easy to maintain.


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I get really frustrated with CTRL-IQ suspending basal insulin, and then going high. I also get really frustrated with having to tweak all the settings to trick it into doing what I want it to do. I don’t have the amazing numbers you all do, my A1C is 6.3-6.5 and my TIR is 95%. But even with CTRL-IQ, I still have to work so hard to get there. I’m tired of it. I’m trying the Medtronic 780G. Hoping their algorithm, which is so different, will be a better fit for me.

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I’ve just been approved for a closed loop system on the nhs here in England which i’m really pleased about and v grateful for. However I am slightly concerned about the pump suspending basal if it thinks I’m going low - in my experience from doing reduced basals on my current medtronic it tends to have effects (highs) way down the line rather than averting a low that is about to happen in the next hour.

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Congratulations with a high five on getting an A1C under 6 right after changing pumps. Did your doctor jump out of a cake to give you your test results?


Just about. :laughing: New endo for me, too, having relocated. So it was auspicious that way too.

My biggest problem is if I take a bolus I don’t get any effect for between 1.5 - 2 hrs. I’m also on sleep 24/7 and I’ve learned to bolus when needed and prebolus long before a meal. I’m also now on Fiasp and it is quicker very slightly. My A1C is between 5.3-5.6 and never higher and I’m always 95-100% time in range. It still takes a lot of work but it’s MUCH better in the last 4 years on the pump.


I admit that I am not in you folks kind of “tight” control but I am not happy with CIQ these days. Mine does not suspend basal soon enough or long enough. During the past year I have had 3 or 4 serious lows and BGs in the 50s and the line shows that my suspension was slow to happen and I was unconscious part of each of those times. It took my liver glycogen to help me recover. Not the drop in insulin infusion. I am relooking at Medtronic again. I just can’t depend on CIQ. I drop fast and don’t hear the warnings. But it should suspend at 70. It looks like it suspends closer to 60.

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I have had reasonable good luck with C-IQ during the 33 months of use, transitioned from MDI using Lantus/Humalog. My HbA1c was in the mid 5% with MDI, but I had some issues with hypos.

With C-IQ my HbA1c ran a consistent 6% flat every 3 months until 6 months ago. The last 2 have been in the mid 5% again. I don’t know if this has anything to do with it, but I changed from Humalog to Novolog.
I have had very few real hypos, maybe 2 for real

This is a screenshot from Clarity AGP for 90 days. Looks pretty good to me. Notice the dips in the early evening. Those occur during some relatively easy exercise after dinner. Sometimes I treat them with glucose, but not always, because when I stop pedaling BG will start rising again. Do what works for you.

Oh, with C-IQ I do not have nocturnal hypos that are real.


Followup. I left grocery store with a BG of 70 on my Tandem pump. I manually stopped insulin delivery as the CIQ had not stopped it even tho I had gotten 2 warnings in the grocery store before checking out and getting to my car. I just don’t get it but apparently my pump must wait until much lower BG before stopping basal. As noted, I am investigating how the Medtronic works with its guardian 4.


C-IQ reduces my basal rate. At 70mg/dl my pump is delivering minimal or no insulin.

Did you contact Tandem support? If you upload your pump data, they can troubleshoot what is going on.

If you had IOB, a drop to zero basal may not be effective to stop the drop in BG, and you need to eat carbs.


I have talked with Tandem pump twice. They have been no help. I can’t eat carbs when I am unconscious but do as soon as I am alert enough to do so. Today I was OK as I stopped the insulin manually and by the time I got home I was back to 84. I go from feeling OK to not knowing anything on those rare quick drop occasions when pump does not stop insulin as it should. Or that is my story anyway.