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

2021 ◽  
pp. 193229682110322
Author(s):  
Jana Schmitzer ◽  
Carolin Strobel ◽  
Ronald Blechschmidt ◽  
Adrian Tappe ◽  
Heiko Peuscher
Keyword(s):  
Real Time ◽  
In Silico ◽  
Closed Loop ◽  
Artificial Pancreas ◽  
Virtual Patients ◽  
Simulation Speed ◽  
Virtual Population ◽  
Speed Up ◽  
Do It Yourself

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.

scholarly journals The UVA/Padova Type 1 Diabetes Simulator Goes From Single Meal to Single Day

2018 ◽  
Vol 12 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Roberto Visentin ◽  
Enrique Campos-Náñez ◽  
Michele Schiavon ◽  
Dayu Lv ◽  
Martina Vettoretti ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
In Silico ◽  
Artificial Pancreas ◽  
Real Life ◽  
Glucose Monitoring ◽  
Glucose Variability ◽  
Self Monitoring ◽  
Inhaled Insulin ◽  
Single Meal

Background: A new version of the UVA/Padova Type 1 Diabetes (T1D) Simulator is presented which provides a more realistic testing scenario. The upgrades to the previous simulator, which was accepted by the Food and Drug Administration in 2013, are described. Method: Intraday variability of insulin sensitivity (SI) has been modeled, based on clinical T1D data, accounting for both intra- and intersubject variability of daily SI. Thus, time-varying distributions of both subject’s basal insulin infusion and insulin-to-carbohydrate ratio were calculated and made available to the user. A model of “dawn” phenomenon based on clinical T1D data has been also included. Moreover, the model of subcutaneous insulin delivery has been updated with a recently developed model of commercially available fast-acting insulin analogs. Models of both intradermal and inhaled insulin pharmacokinetics have been included. Finally, new models of error affecting continuous glucose monitoring and self-monitoring of blood glucose devices have been added. Results: One hundred in silico adults, adolescent, and children have been generated according to the above modifications. The new simulator reproduces the intraday glucose variability observed in clinical data, also describing the nocturnal glucose increase, and the simulated insulin profiles reflect real life data. Conclusions: The new modifications introduced in the T1D simulator allow to extend its domain of validity from “single-meal” to “single-day” scenarios, thus enabling a more realistic framework for in silico testing of advanced diabetes technologies including glucose sensors, new insulin molecules and artificial pancreas.

Diabeloop DBLG1 Closed-Loop System Enables Patients With Type 1 Diabetes to Significantly Improve Their Glycemic Control in Real-Life Situations Without Serious Adverse Events: 6-Month Follow-up

2021 ◽  
Author(s):  
Coralie Amadou ◽  
Sylvia Franc ◽  
Pierre-Yves Benhamou ◽  
Sandrine Lablanche ◽  
Erik Huneker ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Glycemic Control ◽  
Adverse Events ◽  
Closed Loop ◽  
Artificial Pancreas ◽  
Real Life ◽  
Serious Adverse Events ◽  
Life Conditions ◽  
Time In Range

<b>OBJECTIVE </b> <p>To analyze safety and efficacy of the DBLG1 hybrid closed-loop artificial pancreas system in patients with Type 1 Diabetes in real life conditions. </p> <p> </p> <p><b>METHODS</b></p> <p>Following a one-week run-in period with usual pump, 25 patients were provided with the commercial DBLG1 system. We present the results of Time-in-Range and HbA1c over a 6-month period.</p> <p><b> </b></p> <p><b>RESULTS</b></p> <p>The mean (SD;range) age of patients was 43 years (13.8; 25-72). At baseline, mean HbA1c and TIR 70-180mg/dL were respectively 7.9% (0.93; 5.6- 8.5) [63mmol/mol (10; 38-69)] and 53% (16.4;21-85). One patient stopped using the system after 2 months. At 6-month, mean HbA1c decreased to 7.1% [54mmol/mol] (p<0.001) and TIR 70-180mg/dL increased to 69.7% (p<0.0001). TIR<70mg/dL decreased from 2.4 to 1.3% (p=0.03). TIR<54mg/dL decreased from 0.32 to 0.24% (p=0.42). No serious adverse event was reported during the study. </p> <p> </p> <p><b>CONCLUSION</b></p> <p>The DBLG1 System confirms its ability to significantly improve glycemic control in real life conditions, without serious adverse events. </p>

scholarly journals Glucagon sensitivity and clearance in type 1 diabetes: insights from in vivo and in silico experiments

2015 ◽  
Vol 309 (5) ◽  
pp. E474-E486 ◽  
Author(s):  
Ling Hinshaw ◽  
Ashwini Mallad ◽  
Chiara Dalla Man ◽  
Rita Basu ◽  
Claudio Cobelli ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
In Silico ◽  
Artificial Pancreas ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Action Model ◽  
The Difference ◽  
Hormone Control

Glucagon use in artificial pancreas for type 1 diabetes (T1D) is being explored for prevention and rescue from hypoglycemia. However, the relationship between glucagon stimulation of endogenous glucose production (EGP) viz., hepatic glucagon sensitivity, and prevailing glucose concentrations has not been examined. To test the hypothesis that glucagon sensitivity is increased at hypoglycemia vs. euglycemia, we studied 29 subjects with T1D randomized to a hypoglycemia or euglycemia clamp. Each subject was studied at three glucagon doses at euglycemia or hypoglycemia, with EGP measured by isotope dilution technique. The peak EGP increments and the integrated EGP response increased with increasing glucagon dose during euglycemia and hypoglycemia. However, the difference in dose response based on glycemia was not significant despite higher catecholamine concentrations in the hypoglycemia group. Knowledge of glucagon's effects on EGP was used to develop an in silico glucagon action model. The model-derived output fitted the obtained data at both euglycemia and hypoglycemia for all glucagon doses tested. Glucagon clearance did not differ between glucagon doses studied in both groups. Therefore, the glucagon controller of a dual hormone control system may not need to adjust glucagon sensitivity, and hence glucagon dosing, based on glucose concentrations during euglycemia and hypoglycemia.

scholarly journals Use of a do-it-yourself artificial pancreas system is associated with better glucose management and higher quality of life among adults with type 1 diabetes

2020 ◽  
Vol 11 ◽  
pp. 204201882095014
Author(s):  
Zekai Wu ◽  
Sihui Luo ◽  
Xueying Zheng ◽  
Yan Bi ◽  
Wen Xu ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Type 1 Diabetes ◽  
Glycemic Control ◽  
Artificial Pancreas ◽  
Pump Therapy ◽  
Quality Of Life Scale ◽  
Do It Yourself ◽  
Glucose Management

Background: Previous studies show that the use of do-it-yourself artificial pancreas system (DIYAPS) may be associated with better glycemic control characterized by improved estimated hemoglobin A1c (eHbA1c) and time in range among adults with type 1 diabetes (T1D). However, few studies have demonstrated the changes in laboratory-measured HbA1c, which is a more accepted index for glycemic control, after using a DIYAPS. Methods: This is a retrospective before-after study approaching patients who reported self-use of AndroidAPS. The main inclusion criteria included: T1D; aged ⩾18 years; having complete record of ⩾3 months of continuous AndroidAPS use; with laboratory-measured HbA1c and quality of life scale data before and after 3 months of AndroidAPS use; and not pregnant. The primary outcome was the change in HbA1c between baseline and 3 months after initiation of AndroidAPS use. Results: Overall, 15 patients (10 females) were included; the median age was 32.2 years (range: 19.2–69.4), median diabetes duration was 9.7 years (range: 1.8–23.7) and median baseline HbA1c was 7.3% (range: 6.4–10.1). The 3 months of AndroidAPS use was associated with substantial reductions in HbA1c [6.79% (SD: 1.29) versus 7.63% (SD: 1.06), p = 0.002] and glycemic variability when compared with sensor-augmented pump therapy. A lower level of fear of hypoglycemia [22.13 points (SD: 6.87) versus 26.27 points (SD: 5.82), p = 0.010] was also observed after using AndroidAPS. Conclusions: The 3 months of AndroidAPS use was associated with significant improvements in glucose management and quality of life among adults with T1D.

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