Accuracy of Real-Time Continuous Glucose Monitoring System in Hospitalized Patients with Diabetes and Chronic Kidney Disease

Abstract

Objective:

Real-time continuous glucose monitoring (CGM) systems are beneficial for patients with diabetes by providing a comprehensive assessment of glycemic status and reducing hypoglycemia. However, their performance in patients with both diabetes and chronic kidney disease (CKD) during hospitalization remains unclear. This study aimed to evaluate the accuracy of real-time CGM in hospitalized patients with diabetes and CKD.

Research Design and Methods:

We conducted a prospective observational study including 52 patients with diabetes after excluding those with acute kidney injury, active glomerulonephritis, requiring intensive care, or undergoing hemodialysis. Participants were categorized by estimated glomerular filtration rate (eGFR, mL/min/1.73 m²) into G1-2 (≥60), G3 (30–59), and G4-5 (<30). Capillary glucose values were measured with a validated point-of-care (POC) device and paired with corresponding real-time CGM (G6, Dexcom) readings. Accuracy was assessed by mean absolute relative difference (MARD), correlation analyses, Bland–Altman plots, and consensus error grid (CEG) analyses.

Results:

A total of 1603 paired glucose values were analyzed, including 752 in G1/2, 571 in G3, and 280 in G4/5. CGM and POC glucose were strongly correlated (r = 0.91, P < 0.001). The overall MARD was 17.0%, with group-specific values of 19.4% in G1/2, 15.5% in G3, and 13.5% in G4/5 (P < 0.001). Bland–Altman plots showed smaller bias and narrower limits of agreement in advanced CKD. CEG analyses demonstrated high agreement, with >99% of values within clinically acceptable zones.

Conclusions:

The Dexcom G6 demonstrated reliable accuracy in hospitalized patients with diabetes and CKD, with better performance in advanced CKD. These findings support its clinical utility in this population.