Glycemic Variability Assessed by Continuous Glucose Monitoring and Short-Term Outcome in Diabetic Patients Undergoing Percutaneous Coronary Intervention: An Observational Pilot Study

Table 1

Indexes of glycemic variability.

Measure	Formulae	Variables	Significance	Advantages	Limits
Standard deviation (SD)		= mean of glycemic observations; = number of observations	Variation or dispersion from the average	Easy to determine	It does not weigh greater and lower glycemic excursions; it does not address non-Gaussian skewed asymmetrical distribution or outliers
Coefficient of variability (CV)		SD = standard deviation; = mean of glycemic observations	Normalized measure of dispersion from the average	Easy to determine	Same limitations as SD
Mean amplitude of glycemic excursions (MAGE)		= blood glucose changes from peak to nadir; = number of valid observations; = 1 SD for a 24-h period	Average size of glycemic excursions; (MAGE-up: from nadirs to peaks, indicating hyperglycemic fluctuations; MAGE-down: from peaks to nadirs, indicating hypoglycemic fluctuations)	It weighs hypoglycemic and hyperglycemic fluctuations equivalently	The definition of “significant” glycemic peaks and nadirs is arbitrary
Continuous overall net glycemic action (CONGA-)	,; ,	= time; = number of observations; = number of observations over  × 60 min from a predetermined time	Intraday glycemic swings occurring over predetermined intervals (CONGA-1 = 1-hour interval; CONGA-2 = 2-hour interval; CONGA-4 = 4-hour interval)	Accurate measure of intraday glycemic variability	Difficult to calculate