Tandem Diabetes Care, once looking like it would be the latest insulin pump company to go bust, is back with a vengeance with the recent announcement of its latest system, the turbo-charged t:slim X2 with new control technology called Basal-IQ.

This much-anticipated system connects the t:slim X2 pump with the Dexcom G6 CGM (continuous glucose monitor), providing glucose prediction and auto insulin shut-off when a low is predicted. Here at the ‘Mine we talked to a bunch of early users who provided glowing reviews last month. 

Now I have been using this system myself for the past month, and am finding that it adds a whole new level of CGM integration and control that we’ve never seen before. (I’m personally christening it the BiQ, just because I need an acronym, and that looked cool to me).

In a nutshell: The BiQ is a lovely, brilliantly designed pump — both physically, and perhaps more importantly, in its programing. Kudos to Tandem especially for putting a CGM status screen front and center with no need to unlock the pump to view it. Oh, and the way the pump shuts off basal really does avoid a lot of lows, increases safety, and makes it possible to be more aggressive on insulin delivery in order to reduce complication risk. Pumps have come a long way, baby!

Still, the BiQ is not perfect. Here’s my take on using it – the good, bad and ugly of this newest device.


Basal-IQ Specifics

Let’s start with how the system works. The BiQ uses CGM to power the bottom half of the blood sugar curve. It will shut off basal delivery in two cases: When you go below 70 mg/dL, or when its predictive algorithm suspects you’ll go below 80 mg/dL within the next 30 minutes. It automatically resumes again when the sugar passes nadir and starts rising again.

I’m happy to see this predictive feature. Real-time data is great. Future data is better. 

The pump has the same basic touchscreen form factor as its predecessors, so to save space I’ll focus on what’s new and different. (If you want a better understanding of day-to-day operation of Tandem pumps, you can check out my series of reviews on the first gen t:slim, here).

Anyone who’s ever used a Tandem pump knows the three-button wakeup and confirmation screens can be a bit much. But fortunately with the BiQ, they’ve changed the design to offer more viewable info without needing to unlock the device.

You just need to wake the pump up by pressing the one physical button on the entire device (on the top) and you are presented with a very nice, full-color CGM status screen, defaulted to a three-hour look-back view of the CGM trace. The current BG and trend are displayed, along with the battery and transmitter status, the volume of insulin in the pump, and current IOB (insulin on board). You can scroll through 6, 12, 24, and 1-hour trace screens, all without unlocking the pump. To unlock the pump, the traditional three circular targets have been replaced by three small rectangles at the bottom of the CGM status screen, which sadly are a bit small for big fingers. 

The BiQ comes complete with a colorful 320-page manual that I’ve never cracked open. I haven’t needed to, thanks to a combination of the simple operation, the good online training, the BiQ’s built-in prompts, and excellent in-person training (from someone wearing a BiQ on her hip, to boot!).


Most Up-to-Date CGM Technology

The CGM that powers the IQ part of the BiQ is the Dexcom G6. Prior to my BiQ trial, I’d been rockin’ the G5, so this was my first experience with the Gen 6. I had wanted to wear both at the same time to compare, but the Dex folks cautioned me not to as the Bluetooth signals from a G5 and a G6 can apparently get scrambled and wreak all kinds of havoc.

G6, of course, is approved for direct bolus decisions without need for a confirmatory fingerstick. Actually, with the G6, in theory, you’ll never need another fingerstick again. Ever. It self-calibrates, and seems to do a pretty good job at it, but if it does wander off track, you can calibrate it. The sensor runs 10 days, but unlike the G5, isn’t as simple to reboot for a second session.


How Smart is Basal-IQ? 

Of course, what you really want to know is how well the new automated basal restriction system works — the IQ of the BiQ. I gotta say, it’s pretty remarkable. In both garden-variety and steep blood sugar drops, the pump shuts off delivery in time to allow a recovery above 80 mg/dL the majority of the time. It’s crazy wonderful.

Where the BiQ isn’t as good, is with what I call low “coasting lows” – the ones where I’m steadily but surely heading low over a period of several hours. In almost every case, the BiQ didn’t catch these, and I ended up sucking down orange-flavored Transend glucose gel.

I suspect a good way to deploy the BiQ pump is to set your insulin rates slightly on the high side for everything: basal programs, insulin-to-carb ratio, and correction factor. This way highs can be shortened and their peaks blunted, without the corresponding risk of low blood sugar as the pump cuts the basal flow as the sugar trends downwards. 

Remember that it’s only the bottom half of the blood sugar curve by that’s controlled by shutting down basal delivery to deal with hypos or projected hypos. But don’t worry, the next iteration from Tandem will be the Bolus-IQ/Control-IQ model coming in 2019, that will allow for bolus doses to deal with high blood sugars. It’s exciting to see this one-two punch in short order to Tandem, and I can’t wait. This might be a good time to buy some Tandem stock.

But I gotta say, in both this pump and in the Medtronic 670G, I’m amazed at how much control is possible just playing with basal alone.


Basal-IQ “Blows the Competition Away”

It’s important to note that there’s nothing else like the BiQ system on the market. Sure, I’ve mentioned the Medtronic 670G that automatically shuts off insulin when a low is predicted, which also adjusts basal when your blood sugar is heading above the preferred target.

I’ve used both systems, and am finding that BiQ blows the doors off of the 670G, which is saying a lot as it shouldn’t be nearly as capable, given that the BiQ only leverages CGM for lows, making it half the pump the 670G is. But the reason is largely because the connected Dexcom G6 CGM is simply way more accurate and the insulin pump itself is way less intrusive and easy to use, IMHO.

I hooked up Oct. 4th, so for purposes of this initial review my use entailed 22 days. When the BiQ auto-suspends, it looks like 27% of that time is at night — not surprising as I tend to run low in late afternoons. For my entire initial test-drive, I saw two suspensions per day on average.

For me, in just these first 22 days of using this Basal-IQ system, I feel it works better than I had expected. My data speaks for itself: 


What Else is Good About Basal-IQ?

One of the best things about BiQ, and something that really sets it off from its competition, is that it’s not a nag. You have the choice of letting the pump’s CGM-driven basal shutoff and re-start functions run seamlessly in the background without notifications, and this is how I set mine up. I don’t need to know it’s doing its thing. I just want it done. The less I’m bothered, the better.

Note that even with the auto shut-off in the background, the CGM status screen still shows great swaths of red when basal is shut down, so you can always quickly check to see what’s happening if you want to.

As it’s based on the X2 platform, the BiQ is fully Internet upgradable and you can do this from home. Any changes in the future — like CGM control over basal delivery for elevated blood sugars — can be installed simply by plugging your existing pump into your computer. No waiting forever to exchange your pump for the latest and greatest. This is huge and deserves a shout-out.

Additionally, there are other aspects that I like about this device: 

  • The G6 can feed CGM data to the pump, a phone, and an Apple Watch all at the same time.
  • When you need a quick bolus for food or a correction, it’s not a complicated process. The Quick Bolus feature really is easy, and doesn’t require you to unlock the pump. Instead you communicate with the BiQ using Morse Code via the button on the top of the pump.
  • True of previous versions, it has a meal bolus menu allowing you to add in particular food items on the fly to save yourself from extra mental math.
  • Fancy bolus programs are elegant with a combined extended/combo menu. Unlike Medtronic pumps, on each bolus you can choose or ignore these options without adding an extra step.
  • Empty cartridges can be ejected with the handy Tandem Tool or a quarter. Or a poker chip. Just sayin…
  • Alerts are user-selectable to various volumes, vibrate, or off, and you can choose by each type of alarm, so you don’t have just one response for all the pump’s feedback.
  • True of previous versions, the BiQ is exceedingly user-friendly to program.


The Bad and Ugly of the Basal-IQ

Repeat Data Entry for Boluses: My chief bitch about the BiQ is that I need to manually enter my CGM sensor glucose value to correct my blood sugar. That’s just crazy. The pump already knows my BG! And it gets worse. After I’m forced to enter my blood sugar manually for a correction, I’m then asked by the pump if I want a correction for it. Of. Course. I. Do. Otherwise, why the heck else would I have wasted my time entering it? Hey, one way or the other, Tandem, but not both!

Eating When Low? I was also quite annoyed that it isn’t possible to layer on a meal when the BiQ had suspended the basal insulin. Yes. I know I’m at risk of a Low, but if I’m about to eat a banana spilt, it would be a good idea to let me deliver some insulin to cover it without turning the basal back on.

Site Changes: While the site change reminder can be set for anytime, rather than when you actually did it, the system limits us to 1/2/3-day reminders only. No 4-day, darn it, which is my preferred interval, especially on a new pump when I need to “bank” supplies. My workaround is to get my supplies out and leave them on the bathroom counter for the next day when my site reminder goes off, but pump reminders should mirror reality in the field, not try to enforce some ideal of medical perfection.

Limited Profiles: There’s no automatic way to switch between profiles, i.e. the pump will not start a weekend profile at midnight on Fridays, you have to wake up and do it manually. 

Too Quick of a Glance: The quick glance at the CGM screen, done without unlocking the pump, times out and goes blank in 10 seconds with no way to change that. This isn’t long enough and it’d be nice to have the ability to prolong that glance period. (Once unlocked, users can choose screen time outs of 15, 30, 60 or 120 seconds.)

Ugly Case Design: Whoever designed the current case for the BiQ clearly doesn’t wear an insulin pump. At first glance, it looks like a huge improvement — it’s one piece, not two, and not only can the pump be charged or downloaded in the case, but the insulin cartridges can be changed without removing the pump from the case. The case has a lovely stainless clip that can be set for either horizontal or vertical wear, but in both cases upside-down. WTF? Yeah. There’s only one vertical choice (pig tail up) and one horizontal choice (pump upside down for viewer). It seems that making the clip work for all four orientations would have been easy, so I can’t imagine why they didn’t do that. 

Confirmation Screens: This is a good time to talk about the plethora of “are you sure” screens that are part and parcel of operating an insulin pump nowadays. During site changes, the pump guides you step-by-step through the process. At first, I liked having an onboard checklist. But as my comfort level with the system grew, I would have preferred something faster. I’d love to see an option for “beginner” and “advanced user.” For daily activities like when want to eat or need to correct your blood sugar, you have to work your way through five screens just to do those simple tasks.It’s tedious. And because there are so many screens, I sometimes get lost and forget to press the last button to get my bolus. The pump reminds me about five minutes later that I have an incomplete bolus, but by then it’s timed out and I have to start over. Grrrrrrrr…

Smaller Pig-Tail: One of the bizarre things about Tandem pumps is the infusion set connection, now dubbed the t:lock Connector. They have a short “pig tail” of tubing coming out of the top of the pump to connect the infusion set. It’s one of the things I personally hate the most about Tandem pumps. It looks medical, it’s too short to tuck into my waistline, and it makes the tubing more snag-prone. I wish they would work on figuring out something better, like putting the stupid tubing straight into the cartridge and being done with it. Anyway, despite being ugly and a snag-prone, it’s nice that this new slightly smaller Tandem lock speeds up the tubing fill process at site change, thanks to a skinnier aperture, requiring less insulin. When I used their first generation pump I used to make coffee, shred potatoes for hash browns, scramble some eggs and run into town for the mail, all while waiting for the tubing to fill. Now I only have time to make the coffee. So that’s an improvement.

That’s all the criticism I have of this new system.


A Keeper for Me?

Tandem has a real winner here. But the jury is still out on whether it’s a keeper, and I will have to decide in the next month of using the loaner. The first week or two, I had amazing blood sugar control, but I’ve noticed that every time I change my therapy, the first few weeks are great. I’m convinced that diabetes is an intelligent alien parasite that you can catch off guard, but quickly adapts.

To be honest, I’ll have to decide whether I can live long-term with the two things I hate most — the upside-down case and the damn pig tail. I can MacGyver a case solution, and in fact the folks at Tandem were kind enough to send me one to try my hand at. The Dremel tool and the Gorilla Glue are standing by.

But there’s nothing I can do about the pig tail, and that might be the deal-breaker for me. Isn’t it amazing how these “liveability factors” trump everything else when deciding which health tech tools to use? I sure hope industry manufacturers are taking note of that!