Résumé
•Coefficients of variation (CVs) for glucose and HbA1c are key metrics for assessing short- and long-term variability in glucose homeostasis.•A threshold of 36 % for the CVglucose is recommended to separate stable from labile diabetes.•A CV glucose value of < 27 % reduces the risk for hypoglycaemia to a minimal level.•A CV HbA1c of < 5 % for the is proposed as a suitable approach to guarantee a long-term stability of glucose homeostasis.
Near normal glycaemic control in diabetes consists to target daily glucose fluctuations and quarterly HbA1c oscillations in addition to overall glucose exposure. Consequently, the prerequisite is to define simple, and mathematically undisputable key metrics for the short- and long-term variability in glucose homeostasis. As the standard deviations (SD) of either glucose or HbA1c are dependent on their means, the coefficient of variation (CV = SD/mean) should be applied instead as it that avoids the correlation between the SD and mean values. A CV glucose of 36% is the most appropriate threshold between those with stable versus labile glucose homeostasis. However, when near normal mean glucose concentrations are achieved a lower CV threshold of <27 % is necessary for reducing the risk for hypoglycaemia to a minimal rate. For the long-term variability in glucose homeostasis, a CVHbA1c < 5 % seems to be a relevant recommendation for preventing adverse clinical outcomes.