Efficient Closed Loop Simulation of Do-It-Yourself Artificial Pancreas Systems

Abstract

Background: Numerical simulations, also referred to as in silico trials, are nowadays the first step toward approval of new artificial pancreas (AP) systems. One suitable tool to run such simulations is the UVA/Padova Type 1 Diabetes Metabolic Simulator (T1DMS). It was used by Toffanin et al. to provide data about safety and efficacy of AndroidAPS, one of the most wide-spread do-it-yourself AP systems. However, the setup suffered from slow simulation speed. The objective of this work is to speed up simulation by implementing the algorithm directly in MATLAB®/Simulink®. Method: Firstly, AndroidAPS is re-implemented in MATLAB® and verified. Then, the function is incorporated into T1DMS. To evaluate the new setup, a scenario covering 2 days in real time is run for 30 virtual patients. The results are compared to those presented in the literature. Results: Unit tests and integration tests proved the equivalence of the new implementation and the original AndroidAPS code. Simulation of the scenario required approximately 15 minutes, corresponding to a speed-up factor of roughly 1000 with respect to real time. The results closely resemble those presented by Toffanin et al. Discrepancies were to be expected because a different virtual population was considered. Also, some parameters could not be extracted from and harmonized with the original setup. Conclusions: The new implementation facilitates extensive in silico trials of AndroidAPS due to the significant reduction of runtime. This provides a cheap and fast means to test new versions of the algorithm before they are shared with the community.

Developing the UVA/Padova Type 1 Diabetes Simulator: Modeling, Validation, Refinements, and Utility

“…While it is not possible to review all uses of this simulation environment to date, we include a sample to 30 publications spanning 12 years, all of which used the UVA/Padova simulator as a central tool for their developments. 82-111 Overall, a PubMed search (Figure 5) shows that since the introduction of the Minimal Model in 1979, about 555 papers were published on the topics of closed-loop control of diabetes or AID algorithms. Two notable dates mark the beginning of these developments: The 2005 National Institutes of Health (NIH)/Juvenile Diabetes Research Foundation (JDRF)/FDA workshop “Obstacles and Opportunities on the Road to Artificial Pancreas: Closing the Loop” and the 2008 acceptance of the UVA/Padova simulator as a substitute to animal trials for the development of closed-loop algorithms.…”

How do Users Experience Traceability of AI Systems? Examining Subjective Information Processing Awareness in Automated Insulin Delivery (AID) Systems

“…Therefore, for XAI systems to be applicable in medical contexts such as DMT1, simulations of the algorithm need to be developed, for example, that allow this testing of hypotheses before use or as counterfactual during use. Existing approaches for the simulation of glucose level (see [100]) could be supplemented with an interface that offers explanatory variants for situations selected by the users themselves.…”

The automated pancreas: A review of technologies and clinical practice

“…As has been the first step in now commercialized systems, in silico trials of open‐source algorithms show promising results 94,95 . However, no randomized controlled trials have been completed to date 96,97 .…”

“…As has been the first step in now commercialized systems, in silico trials of open-source algorithms show promising results. 94,95 However, no randomized controlled trials have been completed to date. 96,97 In addition, the success stories found in individual case reports, selfreported results or in social media are not a general concern against using this approach when families are aware of the potential risks involved.…”