Page 16 - Glucose Monitoring Devices

The evidence base for SMBG in type 2 diabetes 11

care. In both of the structured SMBG groups, glycemic management was based on
SMBG results alone. At 12 months, the use of structured SMBG provided a signif-
icant reduction in HbA1c of 0.8% compared to the control group, whereas no addi-
tional benefit in glycemic control over the use of structured SMBG was observed
with the addition of once-monthly TeleCare support [85].
Combining the results of individual studies and pooling large amounts of data
gives us insights into the overall measure of the effect of SMBG for noninsulin-
treated T2D. Recent meta-analyses have generally shown a small, short-term reduc-
tion in HbA1 in those individuals performing SMBG compared to those who did not.
The first meta-analysis based on individual participant data from six randomized
controlled trials compared SMBG with no SMBG in individuals with noninsulin-
treated T2D [86]. SMBG reduced HbA1c levels at 3, 6, and 12 months compared
with no self-monitoring by 0.18%, 0.25%, and 0.23%, respectively. The effect of
SMBG on HbA1c levels was consistent across predefined subgroups of participants
according to age, baseline HbA1c level, sex, and duration of diabetes. No clinically
significant reductions occurred in clinical indices such as blood pressure and total
cholesterol. The authors concluded that clinical management of noninsulin-treated
diabetes using SMBG compared with no SMBG resulted in a very modest reduction
in HbA1c levels, which probably has no clinical significance and therefore does not
provide convincing evidence to support the routine use of SMBG for people with
noninsulin-treated T2D. A Cochrane review [87] included 12 randomized controlled
trials and examined the utility of SMBG in individuals with T2D who did not require
insulin therapy. Pooled analysis showed that SMBG led to a statistically significant
decrease in HbA1c of 0.3% after 6 months in participants who have had diabetes for
more than 1 year. Two trials that extended follow-up to 12 months revealed a nonsig-
nificant reduction of HbA1c (0.1%). In participants with newly diagnosed T2D, a
significant reduction of HbA1c (0.5%) was observed at 12 months in favor of
SMBG. It was concluded that SMBG is beneficial in lowering HbA1c in individuals
with newly diagnosed T2D who are not using insulin. However, for those with estab-
lished diabetes for more than a year, the glycemic effect of SMBG was small at
6 months and disappeared after 12 months of monitoring. There was also no evi-
dence that SMBG affects patient-oriented outcomes such as general health-related
quality of life, general well-being or patient satisfaction. In two trials [71e75,88]
that analyzed the cost of SMBG, total estimated costs in the first year of SMBG
were 12 times higher if compared with usual care or self-monitoring of urine
glucose. Following the Cochrane review, a meta-analysis including 15 newer ran-
domized controlled trials and 3383 participants with noninsulin-treated T2D [89]
found that SMBG intervention improved HbA1c with a 0.33% mean difference
compared to controls in the overall effect. In contrast to the Cochrane review,
SMBG improved HbA1c in the short and long term, as well as regardless of diabetes
duration. In addition to HbA1c, significant reductions in BMI and total cholesterol
were observed. The study did not track the intensity of education, lifestyle or dietary
interventions, use of medications, or frequency of SMBG testing. As the differences
in SMBG regimens and the use of SMBG data to adjust blood-glucose-lowering