CGM and SMBG are used for evaluation of blood glucose
fluctuations in daily life. Correlations between HbA1c and
blood glucose fluctuation parameters obtained by SMBG and
CGM have been widely investigated [27–29]. However, HbA1c
has been reported to show no correlations with most blood
glucose fluctuation indices [26,27]. Sartore et al. reported that
among blood glucose fluctuation parameters, SD is affected by
the mean blood glucose level, and is therefore correlated with
HbA1c [27]. In the present study, a correlation was also found
between HbA1c and SD. SD is an index that shows a wide
scatter with respect to mean blood glucose level, and blood
glucose fluctuations are calculated on the basis of the
hypothesis of a normal distribution. In this study, there was
a tendency for participants with HbA1c below 7% to have low
blood glucose levels, and for those with HbA1c at 7% or higher
to have high blood glucose levels, and in the participants as a
whole the blood glucose fluctuations obtained by CGM did not
show a normal distribution. For these reasons, SD may be
inappropriate for evaluation of blood glucose fluctuations in
patients with T1DM.