The accuracy of real-time continuous monitoring system at different stages and its association with glucose excursion

Objective To study the accuracy of real-time continuous monitoring system (RT-CGMS) at different stages and its association with glucose excursion. Methods Totally 33 patients with type 1 diabetes or type 2diabetes were under surveillance of RT-CGMS for 5 d. Capillary glucose values were measured 7 times daily.Correlation coefficient, error grid analysis (EGA), and Bland-Altman analysis methods were used to assess the correlation, accuracy and agreement of RT-CGMS at different stages and in general level; The mean amplitude of glucose excursion (MAGE) and the frequency of glucose excursion ( FGE ) were also calculated. Results ( 1 ) The correlation coefficient of RT-CGMS with capillary glucose values at fasting, postprandial stages, and in general level were 0.94,0.92, and 0.93 respectively( P＜0.01 ). (2) EGA showed that 98.82%, 98.39%, and 98.64% of the results fell in the A and B zones and 1. 18%, 1.61%, and 1.36% fell in the D zone respectively at fasting,postprandial stages, and in general level. There is no result fell in C and E zones. ( 3 ) The agreement analysis showed that RT-CGMS readings were in close agreement with capillary glucose values at fasting, postprandial periods, and in general level. (4)The MAGE at fasting, postprandial periods, and in general level were (3.57±2.66), (4.07±3.09), and (4. 02 ±3.04) mmol/L (P＞0. 05), (0±0. 5), (3± 1), and( 1 ±3) d for FGE (P＜0. 01 ).Conclusion RT-CGMS at fasting stage has higher accuracy than postprandial stage and general level, FGE at fasting stage is higher than postprandial stage and general level. Key words: Real-time continuous monitoring system;  Fasting periods;  Postprandial periods;  Accuracy; Glucose excursion