Biagi Lyvia, Hirata Bertachi Arthur, Conget Ignacio, Quirós Carmen, Giménez Marga, Ampudia-Blasco F Javier, Rossetti Paolo, Bondia Jorge, Vehí Josep
1 Institut d'Informàtica i Aplicacions, Universitat de Girona, Girona, Spain.
2 Federal University of Technology-Paraná (UTFPR), Guarapuava, Brazil.
J Diabetes Sci Technol. 2017 Nov;11(6):1089-1095. doi: 10.1177/1932296817714272. Epub 2017 Jun 21.
Closed-loop (CL) systems aims to outperform usual treatments in blood glucose control and continuous glucose monitors (CGM) are a key component in such systems. Meals represents one of the main disturbances in blood glucose control, and postprandial period (PP) is a challenging situation for both CL system and CGM accuracy.
We performed an extensive analysis of sensor's performance by numerical accuracy and precision during PP, as well as its influence in blood glucose control under CL therapy.
During PP the mean absolute relative difference (MARD) for both sensors presented lower accuracy in the hypoglycemic range (19.4 ± 12.8%) than in other ranges (12.2 ± 8.6% in euglycemic range and 9.3 ± 9.3% in hyperglycemic range). The overall MARD was 12.1 ± 8.2%. We have also observed lower MARD for rates of change between 0 and 2 mg/dl. In CL therapy, the 10 trials with the best sensor spent less time in hypoglycemia (PG < 70 mg/dl) than the 10 trials with the worst sensors (2 ± 7 minutes vs 32 ± 38 minutes, respectively).
In terms of accuracy, our results resemble to previously reported. Furthermore, our results showed that sensors with the lowest MARD spent less time in hypoglycemic range, indicating that the performance of CL algorithm to control PP was related to sensor accuracy.
闭环（CL）系统旨在在血糖控制方面优于常规治疗，而连续血糖监测仪（CGM）是此类系统的关键组成部分。膳食是血糖控制中的主要干扰因素之一，餐后阶段（PP）对CL系统和CGM的准确性而言都是具有挑战性的情况。
我们通过数值准确性和精密度对PP期间传感器的性能及其在CL治疗下对血糖控制的影响进行了广泛分析。
在PP期间，两种传感器的平均绝对相对差异（MARD）在低血糖范围内（19.4±12.8%）的准确性低于其他范围（正常血糖范围内为12.2±8.6%，高血糖范围内为9.3±9.3%）。总体MARD为12.1±8.2%。我们还观察到在0至2mg/dl的变化率下MARD较低。在CL治疗中，传感器性能最佳的10次试验处于低血糖（血糖<70mg/dl）的时间比传感器性能最差的10次试验少（分别为2±7分钟和32±38分钟）。
在准确性方面，我们的结果与先前报道的相似。此外，我们的结果表明，MARD最低的传感器处于低血糖范围的时间较少，这表明CL算法控制PP的性能与传感器准确性有关。
