The proposed terminology ‘A1c-derived average glucose’ is inherently imprecise and should not be adopted

Abstract

The proposed use of a more precise standard for glycated (A 1c ) and non-glycated haemoglobin would lead to an A 1c value, when expressed as a percentage, that is lower than that currently in use. One approach advocated to address the potential confusion that would ensue is to replace 'HbA 1c ' with a new term, 'A 1c -derived average glucose.' We review evidence from several sources suggesting that A 1c is, in fact, inherently imprecise as a measure of average glucose, so that the proposed terminology should not be adopted.

American College of Endocrinology Pre-Diabetes Consensus Conference: Part One

“…There appear to be genetic determinants of A1C (14), with differing degrees of hemoglobin glycation potentially related to differences in erythrocyte survival, different intracellular oxygen tension, 2,3-diphosphoglycerate levels, pH, or different degrees of erythrocyte permeability to glucose. (More information on this point is present in a recent analysis of the topic of variability in the relationship between glucose and A1C [15]). Dekker did, however, review intriguing information from the Hoorn study suggesting a relationship of A1C with CVD risk, both in male and female subjects, with much but not all of the increase in risk explained by other CVD risk factors; she noted that similar reports have been made from analysis of other epidemiological studies and that A1C is also associated with future risk of microalbuminuria and retinopathy.…”

Glycated hemoglobin (HbA1c): old dogmas, a new perspective?

“…The within-subject variability in the degree of hemoglobin glycation has been reported in several studies, as recently reviewed by Bloomgarden et al (32). Almost 70% of this variation is assumed to be genetically pre-determined (e.g., ethnic differences in HbA1c are independent of glycemia), and this individual ''glycation gap'' would hamper the exact translation of one HbA1c value into a corresponding eAG concentration.…”

The proposed terminology ‘A1c-derived average glucose’ is inherently imprecise and should not be adopted. Reply to Bloomgarden ZT, Inzucchi SE, Karnieli E, et al. [letter]

“…Bloomgarden et al have argued against using A 1c as a precise marker of average plasma glucose [1]. Essentially, the authors stressed that the agreement between the measurement of mean plasma glucose and A 1c in the DCCT was only approximately 50% according to a subsequent analysis [2], although the original data reported an agreement of 67% [3].…”