#We are not waiting - DIY APS Do-It-Yourself Artificial Pancreas Systems: The story so far

Introduction In 2015 Dana Lewis, a person with diabetes, developed her own hybrid-closed loop system and began the #WeAreNotWaiting movement (Figure 1). These systems, often called “do-it-yourself” artificial pancreas systems (DIY APS) or open-source closed-loop automated insulin delivery systems, combine an insulin pump, a sensor and an algorithm to maintain glucose levels in range. Whilst early versions were “hybrid” – in other words they still required manual bolusing-the newer versions of the algorithm have been used as a fully-closed loop (no bolus required!) by some individuals. An article written in 2019 provides further detail on these systems and some of the issues associated with them.1 These systems filled a gap by circumnavigating the approvals that commercial companies require in order to launch similar systems. There are three systems commonly encountered: OpenAPS, AndroidAPS and Loop.1 At the time of writing all three systems are unapproved and unregulated. When these systems first entered UK services the evidence was limited. However, self-reported outcomes from users of the systems were encouraging from both glycaemia and safety points of view.2-4 At that time, the approach taken across UK diabetes services was inconsistent and guidelines from the General Medical Council and others were unclear.5 Work was undertaken to explore the opinions of UK healthcare professionals; initial position statements were produced by Diabetes UK and other organisations to support users of these systems.6,7 We also explored the concerns of individuals with diabetes commencing the use of these systems, and were able to demonstrate that they were less concerned with safety and