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ADA 2018: Dr. Dana Lewis on a Do-It-Yourself Pancreas System

Op-Med is a collection of original articles contributed by Doximity members.

Dr. Dana Lewis presented “Improvements in A1C and Time-in-Range in DIY Closed-Loop Users” at the 78th Scientific Sessions for the American Diabetes Association(June 22–26) in Orlando, FL.

Doximity discussed the research with Dr. Lewis at ADA 2018. Below is a transcript of the video interview.


Doximity: Regarding improvements, how far have things come in recent times, and how far do you see them advancing?

Lewis: I’m presenting research today on the outcome study in 2018 of open APs_—_the open source artificial pancreas system. This is significant because there are over 700 people worldwide who’ve been using the systems in the real world for over four years, which means we have an estimated 5 million hours of real world experience with this technology.

It’s not just working_—_it’s working really well because patients are continuing to use this, so we’ve come a long way where we are able to dose insulin off of CTMs and have algorithms that are really good at dealing with all of the real-world situations those of us people with diabetes face.

Doximity: How close are we to a “perfect” closed loop system?

Lewis: A perfect closed-loop system means something different for everybody. I think a lot of people mean a non-hybrid closed-loop system where you don’t have to do boluses or meal announcement, and the reality is thankfully we’re there today. There are people in the DIY community who are not doing meal announcement, not doing boluses and still getting A1Cs around six or below. We’ve made a lot of progress in terms of algorithm and usability to allow people to do that.

But the reality is with a closed-loop system the weakest link is pumps and CGMs: if your pump site gets infected or pulled out, if your CGM sensor is inaccurate, that’s actually the biggest deal for closed-loop systems. It’s not the technology, it’s not the algorithm in the code; it’s actually these other components.

We’re really, really close, but we have other work to do in those spaces to make these systems easy to use and able to stay on our bodies.

Doximity: What is the most meaningful implication of this for clinicians?

Lewis: When you think about closed-loop, whether it’s DIY or commercial, I think it’s really important for clinicians to understand that this is not a cure.

This is amazing technology: It absolutely improves outcomes, it improves quality of life, but it’s not perfect. It’s important for patients and providers to have realistic expectations about what the system can do and can’t do, and understand how to fall back to manual mode if needed.

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