Evaluation of Glycemic Variability in Well-Controlled Type 2 Diabetes Mellitus

Aims: It is necessary to evaluate glucose variability and postprandial hyperglycemia in patients with well-controlled type 2 diabetes mellitus because of the limitations associated with hemoglobin A1c (HbA1c) measurements. We evaluated parameters reflecting postprandial hyperglycemia and glycemic variability in patients with optimal HbA1c. Patients and Methods: Thirty-nine patients with HbA1c levels below 7% were recruited to the study. A continuous glucose monitoring system (CGMS) was applied for two 72-h periods. 1,5-Anhydroglucitol (1,5-AG) and fructosamine (FA) were measured as parameters for postprandial hyperglycemia and glucose variability. Using CGMS data, the following postprandial hyperglycemia parameters were calculated: mean postprandial maximum glucose (MPMG) and area under the curve for glucose above 180 mg/dL (AUC-180). To measure glycemic variability, we calculated mean amplitude of glucose excursion (MAGE) using a classical (MAGE(c)) and new method (MAGE group of sign [MAGE(gos)]). Results: The baseline HbA1c level was 6.3 +/- 0.3%. The mean MPMG was 10.34 +/- 1.84 mmol/L, and the mean AUC-180 was 0.17 +/- 0.23 mmol/L/day. The mean MAGE(gos) was 3.27 +/- 1.29 mmol/L, and MAGE(c) was 4.30 +/- 1.43 mmol/L, indicating glycemic variability in our patients. The mean levels of 1,5-AG and FA were 16.7 +/- 7.4 mu g/mL and 273.0-22.5 mu mol/L, respectively. In a correlation analysis, FA was significantly correlated with MPMG, AUC-180, MAGE(gos), and MAGE(c). In contrast, 1,5-AG was only correlated with AUC-180. Conclusions: This study demonstrated postprandial hyperglycemia and glycemic variability in subjects with well-controlled diabetes. FA may reflect postprandial hyperglycemia and glycemic variability, but 1,5-AG may be of limited value for assessing glucose variability in patients with well-controlled type 2 diabetes mellitus.