A new look at blood sugar readings

My final class at ITP in the Spring was called Printing Code, a graphics design and coding class. For my final project, I took several months of CGM blood sugar data and visualized it in a new way. At that time, I was doing a fair amount of business development work on Databetes. With this project, I was interested in doing something purely for aesthetics, so I went off on this artistic tangent. As a result, I produced these two posters.

October 2012 CGM readings

July 2012 CGM readings

Each displays a month’s worth of blood sugar readings from my Dexcom 7 continuous glucose monitor, which generates a blood sugar reading every 5 minutes. The top of the circle marks midnight. Moving around the circle, time moves clockwise with the morning readings along the right. Noon is at the bottom of the circle, followed by the afternoon and evening readings.

A core element of this visualization is seeing the readings radially instead of the traditional linear approach. I also wanted to try a new approach to categorizing the readings. A normal view of blood sugars look this:

Readings are either In-Range (often categorized as 80-120 mg/dL), High or Low. This time, I had only two categories. I split the difference of In-Range readings at 100 and presented them as either above or below this threshold.

I then converted them to the radial view.

I then stacked all the day views from the month on top of each other with a light opacity. The darker the readings, the more often the readings are in that value range. Outlier days where I have an usual spike in readings can be seen faintly. The poster with the black background from October 2012 shows that I had a few more bad days than I did in July.

I coded these in Processing using the Geomerative library. Big thanks to my teacher Rude Madsen for his help getting things working.

 

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