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This article explores the clinical evaluation of artificial pancreas systems, analyzing patterns from 74 published studies. It discusses the development of a clinical trial database, common themes in trial objectives, and factors influencing trial outcomes. The article also highlights the importance of meal compensation strategies and suggests future improvements based on regression analysis.
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TRENDS IN THE CLINICAL DEVELOPMENT OF AN ARTIFICIAL PANCREAS: GUIDANCE FOR THE FUTURE Lauren M. Huyett, Eyal Dassau, and Francis J. Doyle III Department of Chemical Engineering University of California Santa Barbara Santa Barbara, CA 93106 huyett@umail.ucsb.edu ATTD 2015 Paris, France 20 February 2015
Clinical Evaluation of the Artificial Pancreas • 74 clinical studies have been published to date • What patterns have emerged? • What can we learn from cataloguing and analyzing these studies?
Development of the Clinical Trial Database Studies/Protocol Branches Branch 1 Branch 2 Branch 3
Website Interface to Query Database www.thedoylegroup.org/apdatabase
Website Interface to Query Database www.thedoylegroup.org/apdatabase
Website Interface to Query Database www.thedoylegroup.org/apdatabase
Website Interface to Query Database www.thedoylegroup.org/apdatabase
Website Interface to Query Database www.thedoylegroup.org/apdatabase
Website Interface to Query Database www.thedoylegroup.org/apdatabase III
What are the Study Objectives? Word cloud generated from self-described trial objectives from 2004-2015
Trends in Trial Protocol At least 1 meal with: Only one study so far has incorporated unannounced meals in an outpatient setting.
Reported Mean Subject Age 54 studies reported mean age with standard deviation Studies Ranked by Mean Age
Overall Trial Results Red Shading: Results calculated for >12h of closed-loop From Doyle, et. al, Diabetes, 2014 Studies from 2010-2013
Overall Trial Results Red Shading: Results calculated for >12h of closed-loop Additional Studies 2014-2015 From Doyle, et. al, Diabetes, 2014 Studies from 2010-2013
Overall Trial Results For studies 2010 – 2015 reporting % Time 70-180 mg/dL Meal size is another important factor but is not reported in a standardized fashion.
Regression Analysis of Time in Range Results What protocol or design factors are most influential to percent time in range? Response Variable: Percentage of time in range from 70±2 mg/dL to 180 mg/dL Results reported for 62/88 protocols in database
Regression Analysis of Time in Range Results Dummy Variable Schemes What protocol or design factors are most influential to percent time in range? Response Variable: Percentage of time in range from 70±2 mg/dL to 180 mg/dL Results reported for 62/88 protocols in database
Regression Results No Meals Bolus No Bolus Model retaining just and Metric to compare new results
Conclusions • 74 clinical studies of the AP have been published since 2004 • Searchable database is available for public use at www.thedoylegroup.org/apdatabase • Multiple linear regression shows that meal compensation strategy is the biggest predictor of percent time in range • Many other factors can also affect trial outcome • Starting conditions • Controller tuning or model used • Technological difficulties • Meal size and timing • Future trial results may be compared to expected values from model to gauge improvement
Acknowledgements • Research Group • Dr. Ravi Gondhalekar • Dr. IsuruDasanayake • Dr. Eyal Dassau • Dr. Alejandro Laguna Sanz • Joon-Bok Lee NIH GrantDP3DK101068
Meal/Exercise Details Idea: have a bar graph and then also have the scatter plot of percent time in range versus range or percent time in range versus length of closed-loop
Number of Subjects Also age and gender representation
Inpatient/Outpatient/ In Between Also length of closed-loop
Closed-Loop Results Update on Diabetes Care figure