Looping. I do it.

Artificial Pancreases Device System Illustration

So I’ve been a diabetic (T1) for ~5 years. Used MDI (multiple daily injections) for the first year, then switched to my first pump – the Medtronic 640G. Finger-pricking all that time, until about a year ago when I switched to the Freestyle Libre flash glucose monitor. And most recently, I turned it into a CGM with a miaomiao, xDrip+, and my phone. Next, I’m going try ‘looping’.

For the uninitiated, ‘looping’ is the just the community name for the closest thing we have to an artificial pancreas. The loop is the wireless connection between an insulin pump, a continuous glucose monitor, and a monitoring/control device (usually a phone.) There’s various combinations of hardware you can use to create a loop. I won’t go into all of them – it’s not the focus of this post – but you can find out the high-level details with a quick google search.

Freestyle Libre Monitor and Sensor next to MiaoMiao Bluetooth Smart Reader

Now, as most of you (people that use a pump) will know, pumps are between roughly eight and $10K. In Australia, your health insurance will usually cover one every four years, so you don’t want to make the wrong choice and be stuck with it for almost half-a-decade.

I’m about a year off getting my replacement, but I won’t be getting a loop-compatible pump. Why? you ask. Because the pumps that can be looped are old. The nice fancy new ones are locked up tighter than iPhone, and can’t be jailbroken to get at the data (which you need in order to create a loop). So, you have to get a ‘dated’ pump, with looser security, if you want to loop.

From my reading, you have three options for 'loopable' pumps. The Dana, Medtronic (older models), and the Accu-Chek Spirit (‘Combo’). All three options have lots pros and cons. I’m not going to go too far into all that because that would be a monster post, but I will explain why I’ve chosen what I have.

There’s only two pumps – from what I could find – that would allow me to loop without having to carry more stuff. That’s the Dana and the Accu-Chek Combo/Spirit. Both need an Android phone – AndroidAPS (software that’ll communicate with your pump) and xDrip+ (software that collects data from your CGM – and you can use various CGMs to create the three-way loop.
As I said, there are other pump options – like older model Medtonics – and they’ll let you use more mainstream apps and the iPhone, but they require you to carry an additional bit of hardware (including a battery to run it!). So on that alone, I was not an options for me. Not to mention, the old Medtronics are tough to find, now that looping is becoming more popular. Longer-story-short, I’m going the Accu-Chek route.

AndroidAPS Screenshot
xDrip+ Screenshot

The Accu-Chek Spirit/Combo are an older-style design, but one of the few still in production (i.e. you can get a made-in-2018 one) that are bluetooth-enabled (for use with the glucose monitor/controller) out of the box, and not ‘locked down’ like all the new pumps. This means, with this pump, a CGM and a phone, you’ve got an artificial pancreases.

Accu-Chek Spirit Combo insulin pump

So, I’ve gone online and had a look around for used pumps. Being what they are, they can hold their value pretty well (like an iPhone, or free-weights.) so it took me a while to find one. Managed to snag a 2014 Accu-Ckek Combo/Spirit for $750US from the states (about $1,000AUD, posted) on medwow. That’s about 10% the cost of a new one. So not bad, considering the benefits it’ll (hopefully) have in daily life (or so I’ve rationalised.) If nothing else, I’ll have a backup if my main one breaks/walks-away.

Since my compatible pump is still in the mail, I am giving ‘open looping’ a go. High level, it’s where AndroidAPS will tell you what it would do if it could do it. As it’s not connected to a pump it can control, it just pings you an alert and tells you it’d change your temp. basal up or down, in an effort to keep you in-range. With AndroidAPS, at least, this is part of the on-boarding. It gets you to jump some hoops – ‘objectives’ – so you can get a feel for looping before you actually close the loop. It is tedious though. For instance, the second objective is to make 20 manual adjustments (i.e. when it tells you to make a temp basal, do it.) and do it over 7 days. Only problem is, you’ll make the 20 adjustments in 1, maybe 2, days. Then you have to do another 100+ over the next 5 days before the objective’s complete. It does make you wonder, however. If it’s making this many tweaks every day, imagine how much less hands-off I can be!

That’s it for now. As of writing this, the pump’s still in the mail. I’ll check back in once it arrives (hopefully working and as advertised) and I’ve got it hooked-up.

UPDATE ~4 years on - I'm on my second Accu-Chek pump now. The 2nd hand one worked well. As expected and did the job. When my 640G was out of warranty, I got a new Accu-Chek pump and things have been seamless (NB: from what I understand, the Combo pump is no longer being sold, so things will in this space. They'll still be about in the second-hand market for some years, but they'll become harder to find as time goes on). Software situation has changed also, in that time. With the release of the Libre2 (which has bluetooth inbuilt) it has allowed me to do away with the miaomiao (or any third-party transmitter) which is nice - because it's one less bit of tech in an already lean looping system. So now its just the data source (the 'CGM' - the Libre2), the pump, and my phone to control it all. In this time, the software landscape has changed too. Unfortunately, xDrip+ did not allow direct connection to the Libre2 and AndroidAPS, so a new, less well-established app emerged relatively recently called Diabox. It's not as polished in the back-end, but it's effective and has an active developer, so is working well. Distribution is through Telegam, as it's not compliant with google play or iOS app store.