Assessment of the accuracy of real-time continuous glucose monitoring system and its correlated factors / 中华内分泌代谢杂志

ABSTRACT

Objective To assess the factors that influence the accuracy of real-time continuous glucose monitoring system (RT-CGM).Methods A total of 79 diabetic patients wore RT-CGM for three days continuously while calibrating by interphalangeal glucose values 4-8 times a day.We counted matching rate of interphalangeal glucose values and RT-CGM probe value,and analyzed correlation of the matching rate with MAGE,SDBG,MBG,AUC10,AUC3.9,and NGE by Pearson correlation analysis and multiple linear regression analysis.Then we grouped corresponding match rate by MAGE and MBG,compared the difference among groups.Furthermore,we analyzed correlation of RT-CGM probe values of all-day,fasting-postprandial,and nighttime and the corresponding interphalangeal glucose values by Pearson correlation analysis.Results Pearson correlation analysis showed that the matching rate was negatively correlated with the MAGE,SDBG,MBG,and AUC10.MAGE,MBG,and NGE were in the regression equation.MAGE ＜3.9 mmol/L,matching rate was 81％,3.9 ≤ MAGE＜7 mmol/L,matching rate was 67％,MAGE≥7 mmol/L,the matching rate was 52％,the difference among 3 groups was statistically significant (P＜0.01).MBG＜7.8 mmol/L,matching rate was 78％,7.8 ≤ MBG＜ 10 mmol/L,matching rate was 68％,MBG ≥10 mmol/L,the matching rate was 57％,the difference among 3 groups was statistically significant (P ＜ 0.01).When Youden index was 0.409 and MAGE was less than 3.745 mmol/L,the match rate was more than 75％.When Youden index was 0.369 and MBG was less than 8.38 mmol/L,the matching rate was more than 75％.The correlation coefficients of all day,fasting,postprandial and nighttime probe values and the corresponding interphalangeal glucose values were 0.958,0.963,0.944,and 0.965 (all P＜0.01).Conclusions The probe values show good consistency with the interphalangeal glucose values,are able to be used for blood glucose assessment.Blood glucose fluctuations influences accuracy of RT-CGM,the smaller the blood glucose fluctuations,the smaller the mean glucose concentration,the smaller the effective blood glucose fluctuations in frequency,the higher would be the accuracy.It seems to be more effective to do calibration during fasting and nighttime.