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Clinical question
In patients with type 2 diabetes who are not using insulin, does home
monitoring of blood glucose improve care?
Bottom line
Intensive monitoring of blood glucose in patients with type 2 diabetes not
using insulin results in a small decrease in hemoglobin A1c (HbA1c) levels
but does not change fasting blood glucose levels. Urine glucose monitoring
works just as well. More casual monitoring of blood glucose, such as once a
day, has not been studied. There is a strong possibility that the weak study
design was largely responsible for the difference seen in the study. Blood
glucose monitoring is expensive: At the intense level of monitoring used in
some of these studies (6 times a day), the cost of the monitoring strips
alone can be $2000 US per year.
Reference
Welschen LM, Bloemendal E, Nijpels G, Dekker JM, Heine RJ, Stalman WA,
Bouter LM. Self-monitoring of blood glucose in patients with type 2 diabetes
who are not using insulin. Diabetes Care 2005; 28:1510-17.
Study design: Meta-analysis (randomized controlled trials)
Setting: Outpatient (any)
Synopsis
The researchers conducting this meta-analysis started by searching 3
databases for randomized controlled studies evaluating blood glucose
self-monitoring with typical care in patients with type 2 diabetes who were
not using insulin. They also searched the reference lists of identified
studies for other studies. They did not attempt to find unpublished studies,
research that's usually rejected because it doesn't find a difference. Two
authors independently reviewed the studies for inclusion and evaluated the
methodologic quality, and 2 authors independently extracted the data. The
study quality was moderate for 4 of the studies and high for 2 of the
studies. However, patients in the 6 studies included in this analysis were
not blinded. Concealed allocation was either not done or not described in
any of the studies, allowing the very real possibility that the patients in
the blood glucose monitoring groups were different from those in the control
groups. They were also highly motivated patients; patients doing the
self-monitoring checked blood glucose levels from twice every other day to 6
times per day, 6 days per week. The comparison groups in the study either
did no self-monitoring or monitored urine glucose. In the 5 studies that
compared blood glucose monitoring with no monitoring, HbA1c levels were
nominally but significantly lower in the blood glucose monitoring group
(-.39%; 95% CI, -0.56 to -0.21) after approximately 6 months of follow-up.
Blood glucose monitoring did not produce better HbA1c levels than urine
glucose monitoring. Fasting blood glucose levels were not different in the 2
studies that evaluated it, and quality of life was not different with blood
glucose monitoring in the 2 studies that evaluated it. In one study of more
than 700 patients in which it was monitored, no serious hypoglycemic
episodes occurred in any patient.
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