Self-monitoring of blood glucose (SMBG) has very little effect on glycemic control in patients with type 2 diabetes who are not using insulin. In a review of data from 9 trials of SMBG involving 2324 participants, any effect on HbA1c levels was found to occur only in the first 6 months, during which time the HbA1c level decreased by 0.26% (95% confidence interval [CI], -0.39 to -0.13). Data from 2 trials involving 493 participants showed that the effect of SMBG was no longer significant at 12 months follow-up, with a decrease in HbA1c levels of 0.1% (95% CI, -0.3 to 0.04).
Uriell L. Malanda, MD, and colleagues from the VU University Medical Center in Amsterdam reviewed 12 studies involving 3259 patients with diabetes who are not insulin-dependent. The results are published in the latest issue of the Cochrane Library. "Regular self-monitoring of blood glucose in non-insulin-treated patients has minimal impact on glycemic control, has no impact on general well-being or quality of life, and is rather expensive," Dr. Malanda explained in a press release. "Consequently, it does not add to a clinically relevant long-term benefit."
Hypoglycemic episodes were reported more often in the SMBG group than in the control group in 4 of the studies that were reviewed. The authors explained this to be a result of patients using the SMBG device to confirm perceived hypoglycemic episodes.
In 9 of the trials that were reviewed, SMBG was compared with typical care without monitoring. One study compared SMBG with self-monitoring of urine glucose (SMUG). One study was a 3-armed trial comparing SMBG and SMUG with usual care. One study was a 3-armed trial comparing less intensive SMBG and more intensive SMBG with control participants. The reviewers found that 7 of the 12 studies demonstrated a low risk of bias for most of the indicators.
Two of the trials reported costs of self-monitoring. One trial compared the cost of SMBG with SMUG on the basis of 9 measurements per week, using 1990 prices in US dollars for self-monitoring. The authors concluded that the cost of SMBG (including the cost of a reflectance meter) were 12 times the cost of SBUG ($481 vs $40).
The second trial reported on the full economical evaluation of the costs and effects of self-monitoring. The costs were €104 for the control group, €212 for the less-intensive self-monitoring group, and €203 for the more intensive self-monitoring group. The authors documented higher losses to follow-up in the more intensive self-monitoring group. They felt that this contributed to the difference in costs between the more intense and less intense self-monitoring groups.
SMBG has been shown to be an effective tool for people with type 1 diabetes as well as for those with type 2 diabetes who use insulin therapy. Patients use the glucose levels to adjust insulin doses. This systemic review suggests that patients with type 2 diabetes are not using SMBG to adjust their diet and lifestyle. The authors note that more research is needed to determine the effect of SMBG on hypoglycemia and complications from type 2 diabetes.
The study was supported by the EMGO Institute for Health and Care Research, the Netherlands. Dr. Malanda and several other authors report taking part "in an ongoing study on the topic of interest in this review."
Cochrane Database of Systematic Reviews. 2012, Issue 1. Article