There's a lot of excitement about the new Control-IQ feature coming soon from Tandem Diabetes Care, makers of the touchscreen t:slim X2 pump -- which will create a more fully automated insulin delivery system. In the meantime, many users are enthusiastic about Tandem's current Basal-IQ system, which can predict low blood sugars and suspend insulin delivery to address them in advance.
I've had the privilege of trial testing Basal-IQ recently, and have some positive impressions to share, along with a wish list for improvements.
Note that I'm in a special situation doing this review, as I've been unplugged from an insulin pump for the past three-and-a-half years, opting instead for an insulin pen and fast-acting inhaled insulin. Now for the past few weeks, I've been using the t:slim X2 with Basal-IQ, in hopes of transitioning to Control-IQ once the FDA green lights that next-gen feature (which could literally happen any day now).
I'm also eager to see Tandem unveil its new mobile app allowing data display for important functions like insulin doses and CGM readings -- alongside Control-IQ, which is being hailed as a potential game-changer like no diabetes management system we've seen before on the commercial market.
Basal-IQ with automated insulin shutoff
First up, a refresher on the basics of Basal-IQ:
The system consists of Tandem's groundbreaking touchscreen t:slim X2 pump that can be remotely updated from home, so customers don't need to trade in for a new piece of hardware every time some functionality gets upgraded. The pump connects with the Dexcom G6 CGM (continuous glucose monitor), providing glucose prediction and auto insulin shut-off when a low is predicted 20 minutes in advance. FDA has cleared it for use in making dosing decisions without the need for fingerstick calibrations to reset accuracy. The CGM data is displayed directly on the t:slim X2 pump touchscreen with all the typical graphs and data displays.
What's unique is that Basal-IQ can automatically shut off insulin delivery when your glucose level's predicted to drop below 80 mg/dL or if you cross below that 70 mg/dL mark. Instead of automatically stopping delivery for a set period of time, the system immediately resumes insulin once CGM data shows your glucose levels are starting to rise again.
Basal-IQ: impressive results
Being back on an insulin pump after more than three years of injections and Afrezza inhaled insulin has been a strange experience. But I'm getting used to it, and my device data from the past month shows that it's proving quite effective for my diabetes management. My Time in Range (TIR) has jumped to 71%, which is amazing for me. It's also suspending my insulin about 4 times a day, for an average of 20 minutes at a time and is usually doing that when I'm above 100 mg/dL.
The system has effectively cushioned the blow of hypoglycemia for me too. It hasn't eliminated lows completely, but thanks to the predictive auto-suspend feature, I've avoided plummeting into a situation where I need help. This is huge, and I've noticed that with continued use, Basal-IQ has started giving me more confidence to sleep through the night without fear of dangerous, severe hypos. Because I don't feel the symptoms of lows much of the time overnight (aka hypoglycemia unawareness), this is a big deal for my wife and me.
What is a head-scratcher about Basal-IQ, though: It cuts off insulin based on 3 of 4 past readings where it predicts you're going to go Low; however, all it needs on the flip-side is 1 single reading showing a rise in order to resume insulin delivery. Why wouldn't the same 3 of 4 readings (15 minutes of "trend" data) apply to basal resume, like it does on the Low side? This bothers me, especially because I'm not completely trusting my G6 CGM data and a single digit -- ie rising from 70 to 71 -- allows it to restart basal rates. And no, you don't even need to be back "in range" at the time for it to resume insulin. That's pretty dangerous, IMHO.
Overall, a big challenge for me has been readjusting to being connected to an insulin pump, which I'm not yet sure is the best long-term choice for me. Good to know that connected "smart" insulin pens are becoming more prevalent.
The main system-related challenge I've faced has to do with the Dexcom G6, which I have found less reliable than my trusty previous G5 model -- despite the no-fingerstick calibrations required. I've found the G6 appears inaccurate at times and still needs to be double-checked. I am also struggling to get the full 10 days wear out of each sensor, and have had issues with my G6 connecting to both the Dexcom mobile app and t:slim X2 pump-receiver simultaneously. As a result, I've lost a handful of new sensors and have had to call Dexcom to get those replaced.
Still, now that I've had a few weeks on Basal-IQ, I'm excited for the prospect of their new Control-IQ that will presumably address these issues and bring strong new features.
Wish list for improvements
I know what I would change if I had the chance. Here are my "wish list" items that I hope Tandem Diabetes addresses sooner rather than later:
There's (Almost) an App for That: One of the big missing pieces for Basal-IQ is that you don't have the ability to easily look back and review basic device data on insulin dosing or suspensions, without taking out and reviewing the actual pump or uploading data to their t:connect software online. Since we have the Dexcom G6 mobile app showing off CGM data, it'd be great to have the same for Tandem's tech. Fortunately, Tandem plans to release a new mobile app along with Control-IQ, filling in that existing gap.
Snooze Mode: If you aren't interested in using Basal-IQ's predictive capabilities, you can finger through a few screens and scroll to an option to turn off Basal-IQ for whatever reason. Personally, I've done that most often during times when my BGs are lower and I am taking a food bolus. Especially if that's an extended bolus where part of the dose is delivered now and a remaining portion will be given later, it's handy to turn Basal-IQ off -- because if it predicts a low, that triggers the insulin-shutoff that will cancel any remaining bolus you have going.
In the context of all this, it would be nice to have a "Snooze Mode" for Basal-IQ. This would mirror the existing Temporary Basal setting, where you can program the system to give you 0% or any other percentage for a period of time, and then resume normal activity thereafter.
Notification of Missed Extended Boluses: Building on the above, Basal-IQ's auto shutoff cancels any extended boluses you've started. This frustrated me many times, forcing me to do extra D-math to calculate the insulin I didn't get over a certain time when the basal was turned off. I wish there was a way for the system to keep track of any Extended Bolus that it had cancelled, and let me know about the missed amount of insulin.
Remember way back in 2013, when Tandem Diabetes bought a whole bunch of intellectual property from Smith's Medical that had once been part of the Deltec Cozmo insulin pump? There were over two dozen patents, and a notable one included a feature where the Cozmo calculated how much basal insulin you might have missed during a suspension period. That would do the trick.
Switch Carb and BG Buttons: I remember this from many years ago using the pre-X2 version of the t:slim, and it's still an issue. The Carb and BG buttons seem backwards, to me. A few times, I found myself keying in a carb amount inadvertently into the BG area... and my t:connect data screen shows that, with a BG of 26 mg/dL marked as my lowest glucose reading entered -- but that was a mistake, as it was supposed to be 26 grams of carb being consumed. I can only imagine how troublesome this could be when factoring in quick fingers on the touchscreen or when you're half-asleep.
All-Insulin Records: OK, this one might be tricky, but I'd like to be able to record insulin doses other than what I'm getting from the t:slim X2. That is, I've still been using Afrezza inhaled insulin, which is significantly faster-acting than the Novolog inside the pump. I wish I could manually enter records of Afrezza or other insulin. Doubtful this will ever happen, though, since both Basal-IQ and Control-IQ are largely dependent on the t:slim X2 pump settings and functions. I understand people using the DIY Loop system have the same issue of not having an easy way to record "outside insulin."
Better Clip/Holster: This is certainly cosmetic, but it's still important. I can't stand the clip Tandem provides for this pump. It's a metal clip that can be worn vertically or horizontally, but it must be removed from your belt and manually adjusted to change the orientation. I wish the clip would just rotate, and that I could easily slide the X2 in and out of the holster as needed to see the screen. Honestly, this is one area where Medtronic used to shine; their older 5-series pumps had good plastic holsters with rotating clips.
There are some third party companies like T1 Tactical and EDC Solutions that make cool pump holsters, but those are more costly and there's a wait list. Instead, I found at Walmart a $6 old flip phone case with velcro strap that is a perfect fit for my t:slim X2. It even protects the screen, though I've heard that the material could cause some Bluetooth signal interference.
There are other minor issues, not specific to Basal-IQ but more about the t:slim X2 pump itself -- the large amount of insulin needed to prime the tubing, the little pig-tail part of said tubing, and the massive number of confirmation alerts built into the touchscreen device. My clumsy fingers often missed their target and -- thanks to the "3 strikes rule," where the screen locks if you touch an inactive part of it three times in a row -- I had to start over fairly often.
Still, none of that annoyed me enough to turn me off from using the pump or Basal-IQ system.
Tandem's future diabetes tech
Meanwhile, the expectations for Tandem's new Control-IQ system are running sky-high. It will add auto-adjustments for basals on both the low and high blood sugar sides, and be the first to allow auto-correction boluses. It will still require users to key in meal boluses.
Many believe it will surpass Medtronic's nex-gen closed loop technology (the "Advanced Hybrid Closed Loop," or 780G), which may hit market by mid-2020. Medtronic has said the 780G's new algorithm will be more accurate and reliable, providing automatic correction bolusing, automatically adjusting for missed meals, and allowing an adjustable target down to 100 mg/dL (compared to their current 670G's set 120 mg/dL target). Importantly, that Bluetooth-enabled pump will allow for remote software updating, as offered now only by Tandem. Many believe the competition will come down to users' preference of CGM: Dexcom G6 versus Medtronic Guardian, and to date the former has gotten the most praise consistently by those in the D-Community.
Tandem has also recently signed on to work with Abbott Diabetes Care to integrate a future iteration of their FreeStyle Libre CGM, bringing more choice for those interested in this kind of closed loop technology. No timelines or specifics have been announced yet on that collaboration, and Abbott is still waiting for the FDA to approve its Libre 2 that will offer optional glucose alarms but still require sensor scanning. For all practical purposes, it could be 2021 at the earliest before we see a Tandem-Abbott device.
Just as intriguing is Tandem's future micro-pump device, dubbed the t:sport. It will be a hybrid of sorts, roughly half the size of the t:slim pump and without any display screen at all. The t:sport will have a stick-to-your-body adhesive part, but also the t:slim's trademark pigtail insulin tubing that attaches to the infusion set for insulin delivery. Tandem is planning to file that with FDA in Summer 2020, and the hope is to give customers a choice of how they want to use it: either via smartphone app, or using a separate receiver device. All of that depends on FDA decision-making and remains TBD at this time.
We've also heard renewed rumblings of Tandem's once-upon-a-time plans to develop a dual-chambered closed loop system, one that could deliver both insulin as well as another hormone such as BG-boosting glucagon. Tandem tells us they have shelved the IP originally envisioned in 2013 through a JDRF collaboration, but it could be revived and explored now that we're getting close to having stable, pumpable liquid glucagon. As of now, Tandem's PR folk tell us they are not actively pursuing that in the pipeline.
No matter how you slice it, it's an exciting time for Tandem technology. I look forward to continued use of Basal-IQ in the coming days and weeks, hopefully leading into Control-IQ and its improved features very soon.
Mike Hoskins has lived with type 1 diabetes since age 5. As managing editor at DiabetesMine, he has two decades of experience in print and online journalism, and is an active patient advocate in the Diabetes Community. He lives in Southeast Michigan with his wife and their black lab, Riley (his editorial assistant!).