Tandem Control-IQ update

Tim Street published an interesting update today (13 March 2019) on his Diabettech blog regarding the current status of the Control-IQ tech. Tandem projects that it will release this update this summer (northern hemisphere).

This article links to two other articles about Control-IQ, one from ASweetLife and another at SixUntilMe. Each of these stories is written by people participating in the Control-IQ study.

Here’s Tim Street’s latest on Control-IQ.

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In the lede:

With the recent news that Tandem have suspended their Control-IQ trial due to issues with it’s behaviour under certain CGM circumstances that may cause a hypo (and those in the DIY world can probably read between the lines and guess what that means),

Ok that’s got your name on it, @Terry4—do you want to read between the lines and fill in the rest of us?

The do-it-yourself systems do best when the underlying pump settings are optimized. Basal rates, insulin sensitivity factors, and insulin to carb ratios work best in a closed loop system when they are relatively close to optimum.

Many people switching to a DIY system often realize that their dusty, seldom reviewed, pump settings need to be examined and refreshed. People adopting the Control-IQ system will benefit if they adjust their pump settings to align with actual metabolic needs. Too many of us have adopted a “set-it and forget-it” attitude about pump settings.

I would NEVER be that person! Oh, wait…

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from the article: “in addition, there will always be the feedback from those who run a target range or value that is outside (usually lower) the systems limits. Once again, this is a system targeted at the 72% with Hba1C levels higher than 7.5%, rather than those who maintain a lower value.”

Well my hopes for a nifty upcoming pump feature (Control-IQ) looks like it isn’t going to be so awesome after all. My a1C runs 5.7-6.1.

@Dave44, I think you (and I) may still benefit from this. My A1c runs 6.0-6.2, and we can continue to do what we’re doing while using Control-IQ. It will kick in when things are not going well for us (sickness, going high during sleep, etc). It will help reduce the burden big time.

As far as the high range (112.5-160) what I am thinking is that once I’m using it I will kick up my basal more than normal, so that i will always be trending down closer to 112.5, at which point Control-IQ will begin reducing the basal, etc.

I’m thinking this is one workaround for those who are already below 7.5 :slight_smile:

Does Control IQ supersede Basal IQ or is it in addition to?

It is a completely different algorithm. It is not Basal-IQ version 2. It will begin throttling down the basal when it predicts going below 112. Basal-IQ on the other hand is only On and Off, no throttling.

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All we need now is a heart-rate sensor to detect when we are doing something strenuous to further reduce basals. When I go hiking my rate is turned way down compared to when I’m sitting at home twiddling my thumbs. My gardening suddenly brings me down because it is unscheduled for the most part and the nature of it will drop me very quickly. Hiking is something I always plan ahead for, so as not to end up needing to stop on the trail and gobble Skittles. I hate when that happens–it intrudes on the enjoyment of the hike and often leaves me feeling that icky weakness when my bg’s have fallen too far. If I get low at home, at least there are lots of places to sit down until it passes.

Gardening and Hiking used to be terrible for me as well. But the Basal-IQ really has been amazing in that regard. I strongly recommend trying the Basal-IQ if you can. It has made a world of a difference in my life.

This was my first experience on a hike: Tandem X2 and Basal-IQ

I am torn!
I set my target for 85.
I obviously are not AT THAT BG. But I would like to be closer to that than 112.5
IF I can still manually bolus, or do other things to bring myself down lower than 112.5, then it could still help.
I REALLY like the idea of using this while excising though. I feel this would be a BIG help for me!
Btw, I normally range from 5.6 to 5.8. So I would most likely see a RISE in A1C.
But if I can mentally remove a huge burden, it might be worth it.
Time will tell.

I empathize with you. I am a big fan of letting the user set his/her own preferences. The idea that they seek to protect me from myself is oft-putting. I set my Loop target at 83 mg/dL (4.6). Like you, I don’t end up exclusively at that level, but shooting for what I think is the perfect blood glucose level, my ultimate glucose experience tends toward this level. My average glucose is often 94 (5.2).

I get why they do this, however. This is relatively new technology and designers and programmers want to build in abundant layers of safety. This extra safety, unfortunately, comes at a cost to better performance, however.

I think user customization will eventually be extended once the manufacturers, regulators, and end users get comfortable with automated insulin delivery.

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I think a reasonable question to ask is what benefits will the Control-IQ provide “FOR YOU” which will make that algorithm superior to how you currently operate with Basal-IQ.

You hit the nail on the head - the burden will be reduced dramatically. For me, the burden has been killing me, yet my A1c is 6.0.

So which is more important, a number, or how you feel…?

FYI - A little bird told me that the “sleep” mode CAN be set to all day long. This is the more aggressive algorithm to keep you closer to 112. :slight_smile:


I’ve been using the t:slim X2 for almost two months now. There was a little bit of a learning curve at the beginning but through trial and error I got the basal rates adjusted to a good place. I was still trending a little bit higher than I would have liked and using more insulin than I thought I should be. The overnight lows that I had on MDI were now gone which was great which I chalked up to Basal IQ.

Until I had a derpy G6 sensor a few weeks ago which necessitated me turning off Basal IQ for a 12 hour stretch. It appears that it thinks my drop after a meal is too steep and suspends the insulin so I never would get down to my target BG. I’ve left the Basal IQ off these past two weeks to see how I’d do and I’ve been pleasantly surprised with morning numbers 90-100, have only cracked 200 once, and no lows.

I will give Control IQ a try once it rolls out.

As with everything we use, no one piece of equipment will make everyone happy on all aspects. That is why choice and personal research is so important with this decision.
I am sure like the 670g, there will be people who want tighter numbers. But this is what is necessary to get FDA approval. Safety first.
I will say, I can’t wait for the new program. But it will probably work well for me. My current setting in my pump is 120. We went with that instead of 100 to help with my correction sensitivity. That 20 points was key to keeping me from crashing even with a 1:70 sensitivity.
And I will say it again, if I don’t have to keep thinking about everything every moment, I am all in!
But I will say my goals are not as tight as others. I am perfectly happy with a 7.5 or less and do actually get a little nervous when I get into the low 6’s. But with my predictive low, I can push it a little. And if I continue to fine tune my basal rates ( ongoing all the time), I think this will be an easy changeover for me. Gotta love technology!

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Thanks for this helpful update! Like many here, my average BG is around 110, and I love that. I am super happy with the Basal IQ, and looking forward to trying the Control IQ, but curious how much we can override its program as needed…

I just had to pause to override the “insulin suspended” feature on my pump, which I do often when I’m eating. There are lots of things I know, which the pump can’t, like that I’m dropping but am already eating my lunch, so I actually want my basal insulin.

I assume we’ll still be able to give a correction bolus with Control IQ… (I hope!) And if it can save me just some of the mental work and time involved, as the Basal IQ does, and still have great numbers overall, I’d be very happy!