Review: The First Year on Control IQ

I’ve been using a Tandem t:slim x2 insulin pump since 2018 after I rallied distributor AMSL Diabetes to give me one of the first units to hit our shores (#tslimforfrank). I took advantage of its integration with the Dexcom G5 CGM system in 2019. I trialled Dexcom G6 in 2020, but ultimately costs were prohibitive. When I finally got a better paying job in 2021, one of the first things I did was shell out the $330 a month for the sensors so that I could update my pump’s software to Basal IQ and get some predictive low glucose suspend action into my life.

In March 2022, instructions landed in my inbox to update my pump software to Control IQ – an automated insulin delivery system whereby my pump and CGM talk to each other (if you don’t know what the system does, check out this piece from Diatribe). I quickly completed the training modules, sent the paperwork to my endo to sign, and a few weeks later I had the update code in my inbox.

I left that update code sitting in my inbox until December 2022, in my usual indecisive fashion, while I deliberated over whether (and when) to go through with the update.

Ultimately, I couldn’t give diabetes the love and attention it deserved while trying to juggle everything else going on in my life. I was definitely at a point where I needed this tech in my life, and I figured it couldn’t possibly make things any worse.

I run the system in night time ‘Sleep Mode’ 24/7, which means I receive automatic adjustments to my Basal insulin that targets a blood sugar of 6.1. When run in normal daytime mode, the system also offers automatic correction boluses, however the threshold to trigger these automated adjustments is a higher blood sugar. I didn’t feel the system could bring down a high as quickly as I could, due to its constraints around the delivery of an automated bolus (check out the Diatribe piece here). So I’m happy to take the more aggressive basal adjustments of Sleep Mode and handle corrections myself.

What I’ve learned with this system is that being able to carb count and bolus properly is very important. My endo took one look at my graph back in April and told me to bump up my carb ratio so the system didn’t have to work so hard to mop up the mess (it’s also incredible how sometimes all you need is a fresh set of eyes to point out the glaringly obvious…)

Undoubtedly the biggest impact this system has had is on my sleep. I don’t go to bed wondering what my blood sugar is going to do during the night. I rarely get woken up by CGM alarms anymore. The system keeps me more or less around that 6.1 target for the whole night. I wake up in range every single morning. That’s a third of my day, which my endo pointed out when I didn’t believe my last a1c result.

When I started using the system a year ago, my 30 day stats had me at 52% time in my target range of 4 and 8 mmol, my average BG was 8.5 and my standard deviation was 3.0. My most recent 30 days has my time in range at 61%, average BG at 7.8 and my standard deviation at 2.5.

When I’ve been talking to people about this system, I often comment that the algorithm could be more aggressive. That the system still requires effort on my part – in bolusing for meals and taming high or low blood sugars. It doesn’t completely alleviate the burden of managing diabetes. I would obviously love if those stats were better than what they are – even though I know I am being too hard on myself.

I am managing my diabetes with a lot less effort, even if it’s not as little as I’d like. I am seeing a lot more consistency in my day to day blood sugars. I do feel physically better than I did before Control IQ. I find that my health goals are becoming increasingly broader and less related to blood sugar management these days, which is nice as well.

With my pump warranty up in a few months, I am considering all of my options. As much as I love this system, there is no news in terms of any updates to the algorithm in the pipeline – which is something to consider.

This system isn’t perfect, but then again no system will be able to tick all of my needs and wants. I just have to stick with the one that bothers me the least.

N.B. I have no affiliation with AMSL Diabetes, Tandem or Dexcom.

One Comment

  1. Dan

    Great post, thanks Frank! Matches my experience with it pretty much. I’ve just gone into my second TSlim X2 because I’m happy enough with control IQ. However as you noted, the carb counting is very important — I find if you underestimate by 30g or more you will be riding high for a long time as Control IQ won’t give a bolus correction if you’ve had any insulin bolus in the last hour (my educator recently reminded me of this… presumably it’s included in the initial training.)

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