HbA1C in ESRD

Q: In end-stage renal Disease (ESRD) patients, Glycated hemoglobin (A1C) is a better reflection of blood glucose control than daily or continuous self-monitoring of blood glucose (SMBG).

A) True

B) False

Answer: B 

In ESRD or patients with high grade renal failure, i.e., estimated glomerular filtration rate (eGFR) less than 30 mL/min/1.73 m2, the linear relationship between the average glucose and A1C gets unreliable due to altered red cell turnover, especially in patients who are getting treated with erythropoiesis-stimulating agents (ESAs). Rapid red cell turnover means higher younger red cells, and so the falsely low A1C values. The case was reversed in the past due to analytical interference from carbamylated hemoglobin, which formed due to the elevated urea concentrations. But most labs have abandoned old assay machines.

Another twist to the erratic value of HbA1C comes in patients who are on hemodialysis, as repetitive exposure of the patient's RBCs tends to give high HbA1C levels in even non-diabetic patients.

Either daily glucose monitoring (fingersticks) or continuous glucose monitoring is a better indicator of diabetes control in high-grade or ESRD patients.

#nephrology

#endocrinology

#laboratory-medicine

References:

1. Bloomgarden Z, Handelsman Y. How does CKD affect HbA1c? J Diabetes. 2018 Apr;10(4):270. doi: 10.1111/1753-0407.12624. Epub 2017 Dec 21. PMID: 29124865.

2. Wang X, Peesapati SK, Renedo MF, Moktan S. Hemoglobin A1c levels in non-diabetic patients with end-stage renal disease (ESRD) receiving hemodialysis. J Endocrinol Invest. 2004 Sep;27(8):733-5. doi: 10.1007/BF03347514. PMID: 15636425.

3. Coelho S. What is the Role of HbA1c in Diabetic Hemodialysis Patients? Semin Dial. 2016 Jan-Feb;29(1):19-23. doi: 10.1111/sdi.12408. Epub 2015 Jul 2. PMID: 26138753.