Mean Blood Glucose and Biological Variation Have Greater Influence on HbA1c Levels Than Glucose Instability

Abstract
OBJECTIVE—Mean blood glucose (MBG) over 2–3 months is a strong predictor of HbA1c (A1C) levels. Glucose instability, the variability of blood glucose levels comprising the MBG, and biological variation in A1C (BV) have also been suggested as predictors of A1C independent of MBG. To assess the relative importance of MBG, BV, and glucose instability on A1C, we analyzed patient data from the Diabetes Control and Complications Trial (DCCT).