Mahmoudi Zeinab, Jensen Morten Hasselstrøm, Dencker Johansen Mette, Christensen Toke Folke, Tarnow Lise, Christiansen Jens Sandahl, Hejlesen Ole
1 Department of Health Science and Technology, Aalborg University , Aalborg, Denmark .
Diabetes Technol Ther. 2014 Oct;16(10):667-78. doi: 10.1089/dia.2014.0043. Epub 2014 Jun 11.
The purpose of this study was to evaluate the performance of a new continuous glucose monitoring (CGM) calibration algorithm and to compare it with the Guardian(®) REAL-Time (RT) (Medtronic Diabetes, Northridge, CA) calibration algorithm in hypoglycemia.
CGM data were obtained from 10 type 1 diabetes patients undergoing insulin-induced hypoglycemia. Data were obtained in two separate sessions using the Guardian RT CGM device. Data from the same CGM sensor were calibrated by two different algorithms: the Guardian RT algorithm and a new calibration algorithm. The accuracy of the two algorithms was compared using four performance metrics.
The median (mean) of absolute relative deviation in the whole range of plasma glucose was 20.2% (32.1%) for the Guardian RT calibration and 17.4% (25.9%) for the new calibration algorithm. The mean (SD) sample-based sensitivity for the hypoglycemic threshold of 70 mg/dL was 31% (33%) for the Guardian RT algorithm and 70% (33%) for the new algorithm. The mean (SD) sample-based specificity at the same hypoglycemic threshold was 95% (8%) for the Guardian RT algorithm and 90% (16%) for the new calibration algorithm. The sensitivity of the event-based hypoglycemia detection for the hypoglycemic threshold of 70 mg/dL was 61% for the Guardian RT calibration and 89% for the new calibration algorithm. Application of the new calibration caused one false-positive instance for the event-based hypoglycemia detection, whereas the Guardian RT caused no false-positive instances. The overestimation of plasma glucose by CGM was corrected from 33.2 mg/dL in the Guardian RT algorithm to 21.9 mg/dL in the new calibration algorithm.
The results suggest that the new algorithm may reduce the inaccuracy of Guardian RT CGM system within the hypoglycemic range; however, data from a larger number of patients are required to compare the clinical reliability of the two algorithms.
本研究旨在评估一种新的连续血糖监测（CGM）校准算法的性能，并将其与Guardian®实时（RT）（美敦力糖尿病公司，加利福尼亚州北岭）校准算法在低血糖情况下进行比较。
从10名接受胰岛素诱导低血糖的1型糖尿病患者获取CGM数据。使用Guardian RT CGM设备在两个独立的时间段获取数据。来自同一CGM传感器的数据通过两种不同算法进行校准：Guardian RT算法和一种新的校准算法。使用四个性能指标比较两种算法的准确性。
Guardian RT校准在整个血糖范围内的绝对相对偏差中位数（均值）为20.2%（32.1%），新校准算法为17.4%（25.9%）。对于70mg/dL的低血糖阈值，基于样本的Guardian RT算法平均（标准差）敏感性为31%（33%），新算法为70%（33%）。在相同低血糖阈值下，基于样本的Guardian RT算法平均（标准差）特异性为95%（8%），新校准算法为90%（16%）。对于70mg/dL的低血糖阈值，基于事件的低血糖检测中Guardian RT校准的敏感性为61%，新校准算法为89%。新校准在基于事件的低血糖检测中导致1例假阳性情况，而Guardian RT未导致假阳性情况。CGM对血糖的高估从Guardian RT算法中的33.2mg/dL校正为新校准算法中的21.9mg/dL。
结果表明新算法可能会降低Guardian RT CGM系统在低血糖范围内的不准确性；然而，需要更多患者的数据来比较两种算法的临床可靠性。
