Table 1.

Measures of Glycemic Variability

Method	Calculation	Description	Reference
CV	$\frac{SD}{\overline{x}}$	Standard deviation of glucose values divided by the mean of glucose values.	Rodbard et al.19
CONGAn	$\sqrt{\frac{{\sum }_T^{t=1}{(d_t-{\overline{d}}_t)}^2}{T-1}}$, dt = xt − xt–n hours	Standard deviation of differences between adjacent glucose values for n hour intervals apart.	McDonnell et al.20
IQR	x75th – x25th	Difference between the 75th and 25th percentiles from a distribution of glucose values.	Siegelaar et al.21
M-value	$\begin{array}{l}{M}_x=\frac{{\sum }_{t=1}^T\mid lo{g}_{10}\left(\frac{x_t}{x_I}\right)\mid }{T}\\ M_W=\frac{x_{\mathit{max}}-x_{\mathit{min}}}{20}\end{array}$	Complex log transformation of deviations from an assigned “ideal glucose value” where Mx, if T ≥ 24, Mx − MW, if T < 24.	Schlichtkrull et al.22
MAGE	$\frac{{\sum }_D^{d=1}{A}_d}{D}$	Average of absolute values of differences between adjacent glucose peaks and nadirs for all differences that are greater than 1 standard deviation	Service et al.23
MODD	$\frac{{\sum }_{t=1}^T\mid x_t-x_{t-1\mathit{day}}\mid }{T}$	Average of glucose differences across adjacent days.	Molnar et al.24
SD	$\sqrt{\frac{{\sum }_T^{t=1}{x}_t-{\overline{x}}_t}{T-1}}$	Average of the sum of squared deviations around mean glucose values.	Siegelaar et al.20

Abbreviations: A_d, amplitude greater than 1 SD between the dth peak and dth nadir; CV, coefficient of variation; CONGA_n, continuous overall net glycemic action for n hour intervals; D, total number of amplitudes greater than 1 SD; IQR, interquartile range; MAGE, mean amplitude of glycemic excursions; MODD, mean of daily differences; SD, standard deviation; T, number of time points; x̄, mean blood glucose; x_25th, 25^th percentile of blood glucose values; x_75th, 75^th percentile of blood glucose values; x₁, ideal blood glucose value (set at 131 mg/dL for the study); x_t, blood glucose at time point t; x_{t–n hours,} blood glucose n hours before time t; x_max, maximum blood glucose value; x_min, minimum blood glucose value.