Page 141 - Glucose Monitoring Devices

142 CHAPTER 7 Clinical impact of CGM use

and below target. Whereas, the JDRF study successfully demonstrated a reduction
in glycemic variability across various metrics except for the lability index and
mean absolute glucose change per unit time [55].
The SWITCH study group randomized 124 adult and pediatric participants with
T1DM to 6 months with and without real-time CGM (sensor on and off) and crossed
over both arms following a 4-month washout period [56]. In addition to significant
HbA1c reductions, participants in the CGM arm displayed a change in insulin
administration behavior with a greater tendency to deliver more frequent insulin
boluses [56]. The greater number of people using real-time CGM has seen a rise
in users applying preemptive intervention (including insulin correction) to proac-
tively address blood glucose deviations, a glucose management strategy coined as
“sugar surfing” by Dr. Stephen Ponder MD.
The frequency of hypoglycemia as an index of glucose control and diabetes risk
has become increasingly relevant as a greater impetus toward lowering HbA1c has
seen more individuals receive intensive insulin therapy. The application of RT-CGM
for 26 weeks in adults and children with T1DM has been shown to significantly
lower the time spent in hypoglycemia (interstitial glucose <63 mg/dL) compared
to a control arm with access to blinded CGM every second week for 5 days [57].
Individuals with a history of severe hypoglycemia and hypoglycemia unawareness
are among a vulnerable subset and are likely to benefit most from the features
offered by RT-CGM. Two multicenter RCTs (IN CONTROL and HypoDE), focused
on successfully demonstrating the efficacy of RT-CGM in reducing hypoglycemia,
severe hypoglycemia, and impaired awareness when applied in this high-risk popu-
lation. The use of RT-CGM during the intervention arm of the IN CONTROL trial
significantly improved the time spent in normoglycemia while, in turn, reducing the
time spent in hypo- and hyperglycemia. Furthermore, RT-CGM significantly
reduced the accounts of severe hypoglycemia during the 16 weeks intervention
period versus the control SMBG arm (14 vs. 34 events, P ¼ .033) [58]. Similarly,
HypoDE showed RT-CGM to lower the frequency of hypoglycemic events from
10.8 (SD 10.0) to 3.5 (4.7) per 28 days, and ultimately reduce the incidence of
hypoglycemia by 72% in high-risk individuals [59].

CGM pregnancy data
Well-controlled glycemia is strongly advocated before and during pregnancy to
reduce the risk of complications including preeclampsia, macrosomia, and
congenital malformations. Despite intensive antenatal care follow-up, the rate
of severe hypoglycemia is five times greater in early pregnancy compared to
nonpregnant women and 85% fail to achieve target HbA1c [43,60]. Although
not routinely offered during pregnancy, CGM is often considered when challenged
with severe hypoglycemia and labile glucose control. A prospective randomized
control trial in pregnant women with T1DM and T2DM saw lower third-
trimester average HbA1c levels, lower birth weights, and lower macrosomia risk
when using retrospective CGM compared to usual antenatal care [61]. In a large