From the Guidelines
Hemoglobin A1c (HbA1c) is the best test to assess glycemic control in a patient with diabetic kidney disease (DKD) and nephrotic range proteinuria, as it reflects average glycemia over approximately 2–3 months 1.
Key Considerations
- HbA1c measurement is recommended to monitor glycemic control in patients with diabetes and CKD, with a frequency of twice per year for patients with stable glucose levels, and up to 4 times per year for those with unmet glycemic targets or recent changes in glucose-lowering therapy 1.
- However, the accuracy and precision of HbA1c measurement may decline with advanced CKD (G4–G5), particularly in patients treated with dialysis 1.
- In such cases, alternative approaches to monitoring glycemic status, including self-monitoring of blood glucose, continuous glucose monitoring (CGM), and/or the use of glycated serum protein assays, may be used 1.
- CGM devices can provide additional benefits, such as preventing hypoglycemia and improving glycemic control, especially when used with glucose-lowering therapies associated with a risk of hypoglycemia 1.
- It is essential to consider the potential interference of certain conditions, such as hemolytic anemia, recent blood transfusion, or end-stage kidney disease, on the accuracy of HbA1c measurements 1.
From the Research
Assessment of Glycemic Control in Diabetic Kidney Disease (DKD)
The best test to assess glycemic control in a patient with diabetic kidney disease (DKD) and nephrotic range proteinuria is a topic of ongoing research.
- Continuous glucose monitoring (CGM) has been shown to provide a more accurate assessment of glycemic control than traditional markers such as hemoglobin A1c (HbA1c) in patients with DKD 2, 3, 4, 5.
- CGM allows for the measurement of mean glucose levels, glucose variability, and time spent in hypo-, normo-, and hyperglycemia, providing a more comprehensive picture of glycemic control 3, 4, 5.
- HbA1c has limitations as a glycemic marker in patients with DKD, particularly in those with end-stage kidney disease, as it may not accurately reflect glycemic control due to altered red blood cell survival and erythropoietin therapy 2, 3, 6.
- Glycated albumin (GA) has been proposed as an alternative marker of glycemic control in patients with DKD, as it is less affected by red blood cell survival and erythropoietin therapy than HbA1c 3, 6.
- However, GA may be affected by proteinuria, which can impact its accuracy as a marker of glycemic control 3.
- The use of CGM and GA in combination may provide a more accurate assessment of glycemic control in patients with DKD and nephrotic range proteinuria than HbA1c alone 2, 3, 4, 6.
Key Findings
- CGM has been shown to demonstrate significant undiagnosed hyperglycemia in patients with burnt-out diabetes and end-stage kidney disease 2.
- GA has been found to correlate significantly with mean glucose concentrations in patients with DKD, and may be a more accurate marker of glycemic control than HbA1c in this population 6.
- The progression of DKD has been associated with several CGM parameters, including average glucose level, time spent above target range, and glucose variability 4.
Glycemic Markers
- HbA1c: limited by altered red blood cell survival and erythropoietin therapy in patients with DKD 2, 3, 6.
- GA: affected by proteinuria, but may be a more accurate marker of glycemic control than HbA1c in patients with DKD 3, 6.
- Fructosamine: alternative marker of glycemic control, but may not be as accurate as GA in patients with DKD 6.
- CGM: provides a comprehensive picture of glycemic control, including mean glucose levels, glucose variability, and time spent in hypo-, normo-, and hyperglycemia 3, 4, 5.