The Reply

Abstract

I am happy to respond to the “many questions and concerns” about our study1Davidson M.B. Castellanos M. Kain D. et al.The effect of self monitoring of blood glucose concentrations on glycated hemoglobin levels in diabetic patients not taking insulin a blinded, randomized trial.Am J Med. 2005; 118: 422-425Abstract Full Text Full Text PDF PubMed Scopus (147) Google Scholar raised by Mr. Parkin and Dr. Hirsch. First, the requirement that patients perform self-monitoring of blood glucose 12 times per week (288 times over the 6-month period) far exceeds the usual recommendation of only several times per week for patients not taking insulin. This was done to maximize the potential of self-monitoring of blood glucose to lower A1C levels. The average compliance of 45% (not 40%) was 5 tests per week, somewhat more than the usual recommendations. The breakdown in quartiles of testing all 288 times was as follows: first (lowest), 28%; second, 33%; third, 23%; and fourth, 16%. Second, this was a real-world study in which detailed dietary recall data were not analyzed, although patients were routinely asked to record what they had eaten to facilitate the nutritional counseling. Because the nutritional counseling was the same for both groups (although the dietitian could use the available self-monitoring of blood glucose values to enhance the teaching points), there is no reason to suspect that the nutritional changes were different between the 2 groups. Indeed, similar changes in weight support this conclusion. Third, the protocols followed by the nurse, which were described in the “Methods” section, state that the sulfonylurea agent and metformin were increased every 2 weeks to achieve a fasting plasma glucose concentration of 130 mg/dL or less. However, when (maximal dose) thiazolidinedione was added, we waited 4 months to see whether the patient required insulin. We wanted to give the thiazolidinedione the maximal chance of controlling the patient’s blood glucose level before embarking on a lifelong therapy that necessitates inconvenient and challenging lifestyle changes. Because this was a 6-month study, it ended with many of the patients in the middle of the 4-month treatment period with thiazolidinedione, some of whom eventually required insulin. One year after patients were enrolled in our Diabetes Managed Care Program, the mean A1C level in patients is 7%, and 25% of 367 patients are taking insulin.3Davidson MB, Castellanos M, Duran P, Karlan V. Effective diabetes disease management for a poor and poorly educated minority population (submitted).Google Scholar Except for the 43 patients in the intervention group who performed self-monitoring of blood glucose for 6 months, none of the other patients not taking insulin did so. Fourth, I agree that nutrition therapy probably failed in all patients given the duration of their disease. That is why all but 2 patients were taking oral antidiabetes medication when they entered the study. As far as the suggested design changes are concerned, the object of the study was to evaluate self-monitoring of blood glucose in patients not taking insulin, not in those receiving it. The other suggestion to only enroll patients with A1C levels less than 8% would have made it even more difficult to see any positive effect of self-monitoring of blood glucose. Finally, the contention that “self-monitoring of blood glucose has little value in non–insulin-treated patients is mostly unsupported” is really not true. There have been at least 6 randomized trials and 13 nonrandomized studies addressing this issue.2Davidson M.B. Self monitoring of blood glucose in type 2 diabetic patients not receiving insulin a waste of money.Diabetes Care. 2005; 28Google Scholar In the 5 studies that allegedly showed self-monitoring of blood glucose significantly lowered A1C levels, either self-selection or more intensive counseling in the self-monitoring of blood glucose group could have accounted for the positive results in these few studies. In our present era of evidence-based medicine, so far the evidence from outcome measures does not support the use of self-monitoring of blood glucose in patients not receiving insulin. Perhaps a more accurate statement would be that self-monitoring of blood glucose should not be substituted for effective diabetes management, which happens all too often. Self-monitoring of blood glucose cannot compensate for ineffective diabetes managementThe American Journal of MedicineVol. 118Issue 12PreviewThe recent report by Davidson et al1 on the effects of self-monitoring of blood glucose on A1C concentrations in type 2 diabetic patients not treated with insulin raises many questions and concerns regarding the validity of the study findings and conclusions. Full-Text PDF