Autotuning Diabetes Settings in the Cloud: Part 1

Three years ago our first son was diagnosed with Type 1 Diabetes (T1D). Over the next few months we quickly got used to the process of calculating the amount of insulin required for meals and high blood sugar, and adjusting those calculations on a trial-and-error basis. As a software developer I felt sure there should be a better way.

Thanks to following Scott Hanselman on Twitter I stumbled across some mentions of the OpenAPS project – an open-source artificial pancreas system. Simply amazing stuff! The basics of the system are:

  1. A CGM system that monitors your blood sugar and sends a reading every 5 minutes to…
  2. A processing system running on a Raspberry Pi, Intel Edison or similar that runs all the same calculations as we were doing manually, and sending the results to…
  3. An insulin pump that delivers (or stops delivering, depending on the results of the calculations) the required amount of insulin

This seemed great, and as soon as we could get our hands on a compatible insulin pump we got up and running with the AndroidAPS system that uses the same core logic but simplifies the physical setup by using a standard Android phone as the “brain” and bluetooth communications with the CGM and pump.

However, there’s no clever machine-learning-y stuff going on with those calculations, it’s still essentially performing the same calculations as we always were, it’s just doing it for us automatically and reliably. While that’s definitely a step forward, if the ratios (the insulin:carb ratio that determines how much insulin should be required when eating, and the insulin sensitivity factor (ISF) that determines how much insulin should be required to bring down a high blood sugar level) and basal rates (the amount of insulin continuously delivered in the background) are incorrect then the results aren’t going to be as good as we’d hope for.

The process of refining what those settings should be normally seems to be done simply as trial-and-error, which can get very frustrating! Luckily, one part of the OpenAPS project is Autotune, a system that can run on historical data covering blood sugar, carbs and insulin and recommend changes to those ratios and basal rates based on hard data. Definitely much more appealing to my analytical nature!

The problem is, as a Windows and AndroidAPS user, I found it pretty difficult to use. The details of the ratios and basal rates currently in use weren’t stored in the format that Autotune was expecting, and I had to go back to the documentation each time to work out the format it needed and the details of the command line I had to run. I also had to run it on a Linux VM, just making it that bit more difficult and meaning I only ran it infrequently rather than as a regular process.

To try and make the process simpler for me, and hopefully for others in a similar situation, I started the AutotuneWeb project to:

  1. Automatically convert the profile information stored in Nightscout to the format required by Autotune
  2. Give me the command line details to run, and even,
  3. Run the command for me on my Linux VM and email me the results

I’ve been through a few iterations on how to get this to work, so in Part 2 I’ll run through the various parts that make up this system and how I’ve currently got it running in Microsoft Azure for minimum cost.

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