Estimated average glucose and self-monitored mean blood glucose are discordant estimates of glycemic control

  1. Stuart A. Chalew, M.D.1
  1. Department of Pediatrics1, Louisiana State University Health Sciences Center, New Orleans, LA and
  2. Research Institute for Children, Children's Hospital, New Orleans, LA2


Objective - The A1c-derived Average Glucose study recommended reporting A1c in estimated average glucose (eAG) equivalents. We compared eAG with self-monitored mean blood glucose (MBG) to determine if eAG is systematically biased due to biological variation in the relationship between MBG and A1c.

Research Design and Methods - MBG and A1c were recorded from charts of 202 pediatric type 1 diabetes patients at 1612 clinic visits. Patients were divided into groups with low, moderate, or high A1c bias based on a hemoglobin glycation index (HGI).

Results - MBG vs. eAG (mg/dl, mean±SD): total population, 194±34 vs. 196±36; low HGI group, 186±31 vs. 163±20; moderate HGI group, 195±28 vs. 193±19; high HGI group, 199±42 vs. 230±31.

Conclusions - eAG underestimated MBG in low HGI patients and overestimated MBG in high HGI patients. Disagreement between eAG and MBG downloaded from patient glucose meters will cause confusion if eAG is implemented for clinical use.


    • Received August 11, 2009.
    • Accepted March 27, 2010.

This Article

  1. Diabetes Care
  1. All Versions of this Article:
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