Continuous Glucose Monitoring Metrics in the Assessment of Glycemia in Moderate-to-Advanced CKD in Diabetes

Area of Science:

• Nephrology
• Endocrinology
• Metabolic Diseases

Background:

• Glycated hemoglobin A1c (HbA1c) accuracy is compromised in advanced chronic kidney disease (CKD) due to altered red blood cell turnover.
• Continuous glucose monitoring (CGM) is increasingly recommended for assessing glycemic control in CKD patients.
• The relationship between HbA1c and CGM-derived glycemic metrics in moderate-to-advanced CKD requires further investigation.

Purpose of the Study:

• To evaluate the correlation between HbA1c and CGM metrics of average glycemia and glucose variability (GV) in patients with moderate-to-advanced CKD.
• To determine the reliability of HbA1c as a sole indicator of glycemic control in different stages of CKD.
• To explore the potential utility of CGM-derived indices as adjuncts to HbA1c monitoring in CKD management.

Main Methods:

• Ninety patients with diabetes across CKD stages G3b, G4, and G5 (nondialysis) were enrolled.
• Blood samples for HbA1c and blinded CGM data were collected concurrently.
• Correlations between HbA1c, glucose management indicator (GMI), time-in-range (TIR), and glucose variability metrics were analyzed.

Main Results:

• Correlation between HbA1c and GMI significantly attenuated with advancing CKD stages (G3b: r=0.68; G4: r=0.52; G5: r=0.22).
• HbA1c correlated with TIR and % time > 13.9 mmol/l in G3b and G4 CKD, but not in G5.
• Estimated glomerular filtration rate (eGFR) was a significant determinant of the bias between GMI and HbA1c.

Conclusions:

• CGM-derived glycemic indices can supplement HbA1c monitoring for improved glycemic management in CKD, particularly with eGFR < 30 ml/min/1.73 m².
• Time in hypoglycemia and glucose variability are critical targets for glycemic optimization in CKD, which are not adequately reflected by HbA1c.
• HbA1c alone is an unreliable measure of glycemic control in advanced CKD.