SMBG for T2: A help or a hindrance?   (April 20, 2008)

The British Medical Journal has just published two interesting articles and an editorial: Efficacy of self monitoring of blood glucose in patients with newly diagnosed type 2 diabetes (ESMON study): randomised controlled trial and Cost effectiveness of self monitoring of blood glucose in patients with non-insulin treated type 2 diabetes: economic evaluation of data from the DiGEM trial. The editorial is simply titled "Self monitoring of blood glucose in type 2 diabetes" -- but the subtitle is certainly more provocative: "May not be clinically beneficial or cost effective and may reduce quality of life."

In the ESMON study, 184 people less than 70 years old, with newly diagnosed DiGEM study, looked at the cost effectiveness of SMBG alone or with additional training in incorporating the results into self care, in addition to standardized usual care for patients with non-insulin treated type 2 diabetes. This study did not restrict the study population to recently-diagnosed cases; indeed the diabetes had been present for a median duration of three years. And the care was supplied by generalists, not diabetes specialists.

The authors did an economic analysis of 453 patients with non-insulin treated type 2 diabetes. People with type 2 diabetes who had A1c levels of 6.2% or more and who were not doing SMBG more than once a week were randomized to one of three groups: standardised usual care (control group, n=152), use of a meter with advice for participants to contact their doctor for interpretation of results (less intensive self monitoring group, n=150), and use of a meter with training in self interpretation and application of the results to diet, physical activity, and drug adherence (more intensive self monitoring group, n=151). As in the ESMON study, at 12 months the differences in A1C levels between the three groups (adjusted for baseline level) were not significant. Patients in both self monitoring groups showed reductions in quality of life, which reached statistical significance for the more intensive self monitoring group.

Not too surprisingly, they also found that SMBG (with or without additional training in incorporating the results into self care) was associated with higher costs. They mention that the higher costs of visits for the more intensive self monitoring group than for standardized usual care may relate to the observed changes in health status between the groups, with a need to seek further support or advice, or may be a chance finding.  And they concluded that with "no clinically significant differences in other outcomes, self monitoring of blood glucose is unlikely to be cost effective in addition to standardized usual care." And they add that SMBG "should not be recommended for routine use."

What are we to conclude from these two recent studies? Both indicated that it's possible to improve diabetic control in people with T2DM who are not taking insulin without using SMBG. Both implied that there may be some detrimental effect on patient's psychologic status (based on questionaires, not on actual outcomes), and unsurprisingly there was a documented detrimental effect on pocketbooks: SMBG cost more than not doing monitoring.

Two very important points to bear in mind:

(1) Neither study looked at people with T1DM, women during pregnancy, or T2DM patients who are on insulin. The results must not be generalized to these other patients.

(2) Although these studies do show that if people with T2DM who are not taking insulin can be controlled without SMBG, it requires that such folks  have their A1C levels measured every three months, and be seen every three months and have their diabetes program adjusted based on those A1C levels.

And one final point that I'd like to address specifically to insurance companies: Before anyone from any insurance company who might be reading these studies decides against reimbursing for SMBG for T2DM patients not taking insulin, they should also remember to insist that these patients get A1C levels checked every three months, and be seen by their physicians every three months.