image_printPrint Page

Optimization workarounds for the Tandem Control IQ system – part 2

We have had our hands on Tandem’s Control IQ system for a solid 6 months now. After working not only on my own management with the system, but also having the opportunity to work with many others I wanted to reach out and share some additional optimization workarounds I have found effective.

Just turning the system on will help someone with a >7 A1C get their time in range up, their A1C down, and reduce hypo risk. But, to get farther than that we must have some savvy about how we work the system.

I went over some workarounds that I have found in my earlier article and video back in February.

You can find that article here:


And the video here:

After more time working with others using the system I was eager to bring more optimization tips, but the world kind of got stressful for us all for a while! So now I’m able to sit down and share some tips on how we can use the system to not only help us crack the 7 line, but keep tight control while using Control IQ (CIQ). And as always, none of this is Tandem or FDA approved, these are real-world workarounds and the only tested data on it is the experiences of myself and my clients.

The thing I’ve found most valuable when working with patients to maintain tight glycemic control with CIQ is that we have to shift our thinking about what post prandial blood sugars and corrections should look like. Many of us who keep things at an A1C in the low 6’s (Without restricting foods) have often done so about being pretty aggressive about correcting high blood sugars. We have gotten pretty good at hitting the gas (blousing and temp basaling) power sliding into an 80-100 range, then leveling out (hopefully). But when we do this with Control IQ we get somewhere between a mildly frustrating and a flat out enraging result. Because all the work we put into throwing the throttle down is undone when the system thinks we are going to go low and backs off basal delivery. We either never crack below the 120 line, or we drop to 90 and then go right back up to 120+. (I know, lots of people are rolling their eyes thinking “poor baby having to sit way up at 120! Try 200!! And I hear you! But we want everyone to be able to manage at the level at which they feel their best.)

So the first tip I have is to readjust what you want to see from your post bolus graph.

Rather than that fast drop with a sudden stop, CIQ works best with a slower more gradual lowering of blood sugar. This way we can stealthily let blood sugars drop into the 90-100 pocket and control IQ will then let them ride there as long as we don’t do anything to suddenly drop our blood sugar. (this takes some real setting finesse but it is so pretty when things are really dialed in)

“But Alicia, that means I will spend more time at the elevated blood sugar levels so my Avg will go up! My A1C will go up!” Well for those who keep an A1C of 6 by power sliding into a 90, missing the mark and slipping down to 70 before leveling out, yes you probably will see a small increase in your average because the system is simply not designed for blood sugars to come down that hard that fast. But for most people with an A1C in the low 6s that I have worked with, they actually saw their average go down and their time in range go up when they eased off the speed of their bolus drop. This is because Control IQ helped them reduce the spike and that more than made up for the brief lingering slightly higher. A short-term perceived loss that nets long term gains. One of the hardest things about adapting to hybrid Closed Loop (HCL) technologies( no matter which one I’ve used )has been letting my eye get used to what things look like when the system is working well because it won’t look like my manual management.

My next tip comes for those times when the system’s automated basal changes can muck up my plans.

Most commonly this is when I bolus for a meal following shortly after another bolus. Perhaps it’s lunch following breakfast or dinner following a snack. It may be blousing for lunch after a correction for a site issue in the morning. Or even if I’m going to eat after exercise and blood sugars have been dropping coming into the meal. Either way, I’m now coming into a meal with a downward trend arrow, particularly if it is a quick drop, which means CIQ is doing its job and reducing my basal to prevent a low (the lower half of the CIQ icon is orange). The problem is that my carb ratio is dialed in to work with a full complement of basal insulin under it. If CIQ has been reducing my insulin for the last 30-60 minutes I’m going to end up with less insulin than that meal needs, and things are probably going to rise pretty fast. But much like the thought behind “Super blousing” we can stack some basal insulin into our bolus. But unlike super bolusing, instead of front-ending basal that we WILL get we can add on basal that was omitted from the previous hour or so.

For me, and other patients I’ve worked with the rough idea is to either directly add back in the amount of insulin for any suspension in the hour before a meal. Check your settings in your profile, check the length of the suspension (you can get a really good estimate using the 1-hour CGM graph), and crunch the math. For reductions the math does not work well since we can see that we have a reduced basal running, but not what the last one was or for how it was running without doing some pretty deep history diving and I know I don’t have time for all that. So I have found that for me a 45 degree angled drop to my blood sugar over the hour before a bolus means I’ve probably lost about a half-hour of basal to Control IQ, so I can add that into my bolus, but individual results may vary here.

The final piece I have found is that my exercise activity temp target is often used more after the activity has ended, than during the activity itself!

For short workouts, I find it far more valuable to simply adjust my boluses ahead of my exercise to allow for increased glucose burn during the workout and I leave the exercise temp target alone. If I am doing a moderate level activity that is longer in duration like walking for hours, then I turn the exercise activity target on an hour in advance and run it through the activity (I turn it off about a half-hour before I’m done to reduce a post-activity rise)

But particularly now that hiking, and swimming are a part of my day, I use the exercise temp target after physical activities to prevent delayed onset hypoglycemia regularly. Without it, I find that my blood sugars can sag a bit in the 6 hours after a good hike or hard swim, but with the exercise, temp target on by blood sugars will sit pretty nicely in the 120 range, and tend to do so with fewer of those full suspensions of insulin that can prove troublesome if I’m going to have a meal or snack.

I also have 4 profiles to run control IQ really well these days

  • Manual – just in case I have no CGM or unreliable CGM data, or on the rare occasion, I need to just fix a problem the old fashioned way.
  • CIQ – more aggressive correction factors and slightly adjusted carb ratios for optimal performance
  • CIQHIGH– for hormonal fluctuations, high-stress times, or when splurge day and a missed workout meet YIKES!
  • CIQLOW– I added this one with 30% lower basals and slightly less aggressive correction factors that I use when hiking since a full day’s hike followed by a hot night sleeping can really do a number on dropping my blood sugars below what the exercise temp target can handle, though I keep an eye on ketones when I hike to make sure that reduced insulin levels combined with exercise and sweating don’t put me in a hazardous place.

So there you have it, a few more tips to help us live life on our terms, while also making the most of technology that might otherwise impose some unwanted limitations. I encourage anyone struggling with any HCL system to reach out to IDS for an appointment. These systems have a lot to offer, but really are a paradigm shift in a diabetes management world that hasn’t changed much over the last 20 years! It looks like HCLs are here to stay and we may find that in a handful of years we will be hard-pressed to use insulin pumps without these features.

Here’s another article you may find interesting, “My Personal Review of Tandem Diabetes’ Control IQ (CIQ) hybrid closed loop system

image_printPrint Page