Page 140 - Glucose Monitoring Devices

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CGM efficacy

used to demonstrate improved glucose control when using implantable and transcu-
taneous CGM [48,49], while studies measuring HbA1c have observed the greatest
reductions in participants starting RT-CGM with poor baseline glycemic control
(HbA1c >9%) [50]. These outcomes favor identifying groups that would benefit
most from CGM and applying a targeted approach to clinical implementation. How-
ever, crediting CGM alone for the significant HbA1c improvements ignores the fact
that individuals with the above target HbA1c may struggle to adhere to or may not
have received optimal treatment before CGM. Therefore it is commonplace in clin-
ical practice to ensure that those considered for CGM partake in a form of validated
structured education and a period of optimal treatment before commencing CGM.

Randomized controlled trials
Continuous RT-CGM has been shown to have the greatest effect in reducing
HbA1c in a head-to-head RCT comparing continuous CGM, biweekly real-time
CGM and five-times daily SMBG [51]. This study population of adults and chil-
dren with baseline HbA1c >8% despite intensive treatment further supports the
targeted application of CGM in individuals struggling to achieve optimal control.
Two large RCTs, the Juvenile Diabetes Research Foundation (JDRF) CGM study
and the DIAMOND clinical trial, both showed real-time CGM to reduce HbA1c in
pediatric and adult T1DM populations [52,53]. The JDRF multicenter RCT
compared various real-time CGM devices against SMBG and explored the impact
of age and frequency of CGM use on HbA1c outcomes. Following 26 weeks of
CGM, the subgroup of participants older than 25 years old showed a significant
reduction in HbA1c and increased time in target range (71e180 mg/dL) without
increasing the risk of biochemical hypoglycemia ( 70 mg/dL). This group was
shown to use CGM significantly more frequently than the younger participants
with 83% using CGM at least six times a week. Although the CGM cohort of
8e14-year olds failed to achieve a statistically significant HbA1c reduction,
they had more participants with HbA1c <7% and a 10% relative reduction in
HbA1c. These findings further highlight the importance of selective CGM applica-
tion in adults willing to engage, as reflected in the NICE guideline’s requirement
for at least 70% compliance. Although most individuals with T1DM deliver insulin
by MDI most CGM users manage their diabetes using continuous subcutaneous in-
sulin infusion (CSII). The DIAMOND clinical trial randomized adults using MDI
to either real-time CGM or usual care for 24 weeks to establish the efficacy of
CGM in MDI users [52]. The CGM group produced a 1% and 1.1% reduction in
HbA1c at 12 and 24 weeks, respectively, with over 90% using CGM at least
6 days a week. Similarly, in a crossover RCT comprising T1DM adults with sub-
optimal baseline glucose control (HbA1c >7.8%), the GOLD trial demonstrated
a 0.43% mean difference in HbA1c in the CGM arm compared to conventional
therapy [54]. Both the JDRF and DIAMOND studies reported reduced glycemic
variability with real-time CGM [52,55]. DIAMOND showed that real-time CGM
significantly increased the average minutes per day spent in target range
(3.9e10 mmol/L) and in turn reduced the median minutes per day spent above