OpenAPS Overview and Project History

In order to relieve the incredible burden of T1D, many research teams and manufacturers have developed and are testing Artificial Pancreas Systems (APSs) that connect CGMs to insulin pumps and use various algorithms to automatically adjust insulin dosing (and sometimes dose glucagon, a counter-regulatory hormone) to attempt to mimic some of the functions of a healthy pancreas, and keep blood sugar levels in a safe range. While quite successful in clinical trials so far, current APS systems have been in development for many years, and are still likely at least 3 years away from FDA approval. It is also unclear whether first-generation APS technology will be suitable for, or available to, all patients, even in rich countries.

To address some of the challenges of daily life with diabetes, and because #WeAreNotWaiting, several people worked to figure out how to connect up existing FDA-approved medical devices such as the Dexcom G4 CGM and the Medtronic Minimed insulin pump, using commodity computer / mobile phone hardware and open-source software, to create a complete closed loop Artificial Pancreas System (APS). The first public example of this was the #DIYPS closed loop system, created in their spare time by @DanaMLewis and @ScottLeibrand in the fall of 2013 based on their earlier work to build the #DIYPS remote monitoring and decision assist system. #DIYPS used the Nightscout project’s uploader to get Dexcom CGM data off the device. #DIYPS was able to become a closed loop with the help of open-source decoding-carelink project created by @Ben West to communicate with Medtronic insulin pumps, retrieve data and issue insulin-dosing commands to pumps that support it. #DIYPS was the base system that led to #OpenAPS.

In light of the success of #DIYPS closed loop and other simple APS systems built by individuals, Dana and Scott decided to further apply the #WeAreNotWaiting ethos to APS research, believing safe and effective APS technology can be made available more quickly and to more people, rather than just waiting for current APS efforts to complete clinical trials and be FDA-approved and commercialized through traditional processes.

#OpenAPS is an open reference design for, and will be a reference implementation of, an overnight closed loop APS system that uses the CGM sensors’ estimate of blood glucose (BG) to automatically adjust basal insulin levels, in order to keep BG levels inside a safe range overnight and between meals.

#OpenAPS is not intended to be a “set and forget” APS system. To maximize safety, a system designed from OpenAPS only doses basal insulin. Users still need to bolus for meals as they do today. However, OpenAPS can identify deviations from predicted blood sugar changes and change basal rates to prevent dangerous drops or rises that deviate from expected behavior.

After launching in early 2015, there are at least 44 known instances of OpenAPS that are live and running (as of March 23, 2016), with several others in development and testing phases. For anecdotal experiences from those running OpenAPS, watch the #OpenAPS hashtag on Twitter and also check out the Resources section for a list of those sharing their experiences publicly.

In early 2016, progress continues to be made with the iteration of several hardware options, in addition to multiple new software features.