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Background and Aims: Continuous subcutaneous insulin infusion (CSII) is a widely adopted treatment for type 1 diabetes and is a component of an artificial pancreas. CSII accuracy is essential for glycemic control, however, this metric has not been given sufficient study, especially at the range of the lowest basal rates (BRs), which are commonly used in a pediatric population and in closed-loop systems (CLSs). Our study presents accuracy results of four off-the-shelf CSII systems using a new accurate method for CSII system evaluation. Materials and Methods: The accuracy of four off-the-shelf CSII systems was assessed: Medtronic MiniMed 640G Ò , Ypsomed YpsoPump Ò , Insulet Omnipod Ò , and Tandem t:slim X2 Ò . The assessment was performed using a double-measurement approach through a direct mass flow meter and a time-stamped microgravimetric test bench combined with a Kalman mathematical filter. CSII accuracy was evaluated using mean of dose error. Mean absolute relative difference (MARD) of error was calculated at different observation windows over the whole series of tests. Peakwise insulin deliverance was assessed regarding stroke regularity in terms of frequency and volume. Results: Mean error values indicate a general tendency to underdeliver with up to -16%. MARD of error shows very wide results for each pump and each BR from 7.4% (2 UI/h) to 61.3% (0.1 UI/h). Peakwise analysis shows several choices for BR adaptation (frequency for Omnipod, volume for Tandem, both for YpsoPump and MiniMed 640G). Precision in interstroke time appears to be better (standard deviation [SD] at 0.1 UI/h: 4.6%-12.9%) than stroke volume precision (SD at 0.1 UI/h 38.3%-46.4%). Conclusions: The accuracy of four off-the-shelf CSII systems is model and BR dependent. CSII imprecision could be due to a variability in volume and/or frequency of strokes for every pump. Some models appear better adapted for the smallest insulin needs, or for inclusion in a CLS. The clinical implications of these delivery errors on glucose instability must be evaluated.

Body-worn sensors (BWS) could provide valuable information in the management of Parkinson’s disease and support therapeutic decisions based on objective monitoring. To study this pivotal step and better understand how relevant information is extracted from BWS results and translated into treatment adaptation, eight neurologists examined eight virtual cases composed of basic patient profiles and their BWS monitoring results. Sixty-four interpretations of monitoring results and the subsequent therapeutic decisions were collected. Relationship between interrater agreements in the BWS reading and the severity of symptoms were analyzed via correlation studies. Logistic regression was used to identify associations between the BWS parameters and suggested treatment modifications. Interrater agreements were high and significantly associated with the BWS scores. Summarized BWS scores reflecting bradykinesia, dyskinesia, and tremor predicted the direction of treatment modifications. Our results suggest that monitoring information is robustly linked to treatment adaptation and pave the way to loop systems able to automatically propose treatment modifications from BWS recordings information.

Background: Accuracy of continuous subcutaneous insulin infusion (CSII) is essential for glycaemic control. Our study presents results of accuracy assessment of three off-the-shelves CSII under fluctuating temperature at 0,5UI/h. Methods: CSII systems accuracy was assessed by a double measurement approach utilizing a direct mass flow meter and a time-stamped micro-gravimetric test bench combined with a Kalman mathematical filter. CSII was placed inside a chamber of fluctuating temperature: 8h-tests were composed of successions of 1h at 32°C, 1h at 5°C, and compared to 8-hour tests at a 22°C fixed temperature. Accuracy was evaluated using mean of dose error. Mean absolute relative dispersion (MARD) of error was also computed for 15min time-windows. Stroke regularity was assessed in terms of frequency and volume. Tests were conducted both with insulin and medical water. Results: Delivery errors follow temperature profile. MARD of error is significantly higher with fluctuating temperature (85.2%, 44.4%, 20.4% according to each of the 3 CSII pump models) vs. fixed temperature (13.3%, 9.5%, 12.7%). No difference was observed between insulin and medical water. Stroke volume is affected by temperature changes rather than stroke frequency. Conclusion: Temperature and its fluctuations may affect the accuracy and amounts of insulin delivered by CSII. The clinical impact of the difference in insulin intake requires clinical investigations. Disclosure S. Girardot: Employee; Self; Air Liquide. Employee; Spouse/Partner; Air Liquide. P. Jacquemier: Employee; Self; Air Liquide. F. Mousin: Employee; Self; Air Liquide. C. Rendekeu: Employee; Self; Air Liquide. S. Hardy: None. J. Riveline: None.

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