Author(s): FELLINGER, E., BRANDT, T., CREUTZBERG, J., ROMMERSKIRCHEN, T., SCHMIDT, A., Institution: UNIVERSITY OF THE BUNDESWEHR, Country: GERMANY, Abstract-ID: 1650

INTRODUCTION:
Continuous Glucose Monitoring Systems [CGM] can not only be used for glycemic control in chronic diseases (e.g. diabetes mellitus) but are increasingly being utilized by individuals and athletes to monitor glucose fluctuations in training and everyday life. However, it is not clear how accurately [CGM] measurements reflect plasma glucose concentration in a healthy population in the absence of chronic diseases.
METHODS:
44 healthy male subjects (25.5 ± 4.5 years) performed an oral glucose tolerance test [OGTT]. The interstitial fluid glucose concentration [ISFG] obtained by a CGM sensor was compared against finger-prick capillary plasma glucose concentration [CPG] at fasting baseline (T0), -30 (T30), -60 (T60), -90 (T90), -120 (T120) min post [OGTT] to investigate differences in measurement accuracy.
RESULTS:
Overall mean absolute relative difference (MARD) was 12.9 ± 8.7 %. 100 % of [ISFG] values were within zones A and B in the Consensus Error Grid, indicating clinical accuracy and being in line with the ISO 15197:2013 criteria (having at least 99 % of results within these zones). Paired t-test revealed statistically significant differences between [CPG] and [ISFG] at all time points (T0: 97.3 mg/dl vs. 89.7 mg/dl, T30: 159.9 mg/dl vs. 144.3 mg/dl, T60: 134.8 mg/dl vs. 126.2 mg/dl, T90: 113.7 mg/dl vs. 99.3 mg/dl, T120: 91.8 mg/dl vs. 82.6 mg/dl, respectively; p < 0.05) with medium to large effect sizes (d = 0.57 – 1.02) and with [ISFG] systematically under-reporting the reference system [CPG]. Bland-Altman plot analysis indicated 5.4 % of measurements not falling into the limits of agreement (mean difference ± 1.96*SD of difference).
CONCLUSION:
CGM sensors provide a convenient and reliable method for monitoring blood glucose fluctuations in clinical settings as well as in the everyday life of healthy adults.