Real-time continuous glucose monitoring with subcutaneously inserted sensor correlates better than subcutaneously implantable sensor with glycated hemoglobin, glycated albumin and fructosamine.

BACKGROUND: Real-time continuous glucose monitoring (RT-CGM) is widely used in patients with type 1 diabetes (T1D) to improve glycemic control by reducing postprandial glucose peaks and hypoglycemic episodes. In addition, traditional biomarkers such as glycated hemoglobin (HbA1c), glycated albumin, and fructosamine provide retrospective estimates of glucose regulation over varying timeframes. This study aimed to evaluate the correlation between these biomarkers and glycemic metrics obtained from two types of RT-CGM systems: an implantable sensor (Eversense E3) and subcutaneously inserted sensors (Dexcom G6 and Guardian 4).

METHODS: We analyzed data from 35 patients with T1D: 13 used the Eversense E3 system, and 22 used Dexcom G6 or Guardian 4. Mean blood glucose (MBG) and time in range (TIR) were assessed at multiple time points and correlated with HbA1c, glycated albumin, and fructosamine levels.

RESULTS: In the Eversense group, no significant correlation was observed between CGM-derived metrics and any of the biomarkers. Conversely, in the Dexcom/Guardian group, MBG and TIR demonstrated significant correlations with all biomarkers, showing large effect sizes for HbA1c and fructosamine, and medium for glycated albumin.

CONCLUSIONS: These findings suggest that the Dexcom G6 and Guardian 4 systems more reliably reflect established biochemical markers of mid- to long-term glucose control, while Eversense may be less consistent in this regard. This highlights the importance of sensor selection when interpreting CGM data for clinical or research applications in diabetes management.