Fasting and Postprandial Hyperglycemia: Their Predictors and Contributions to Overall Hyperglycemia in Korean Patients with Type 2 Diabetes

BACKGROUND: This study aimed to identify factors that affect fasting hyperglycemia (FHG) and postprandial hyperglycemia (PPG) and their contributions to overall hyperglycemia in Korean patients with type 2 diabetes mellitus (T2DM). METHODS: This was a retrospective study conducted on 194 Korean T2DM patients with 7-point self-monitoring blood glucose (SMBG) profiles plotted in 4 days in 3 consecutive months. We calculated the areas corresponding to FHG and PPG (area under the curve [AUC](FHG) and AUC(PPG)) and contributions (%) in the graph of the 7-point SMBG data. The levels of glycated hemoglobin (HbA1c) were categorized by tertiles, and the contributions of FHG and PPG were compared. RESULTS: The relative contribution of FHG increased (44.7%±5.6%, 58.0%±4.4%, 66.5%±2.8%; PANOVA=0.002, PTREND <0.001), while that of PPG decreased (55.3%±5.5%, 42.0%±4.4%, 33.5%±2.8%; PANOVA=0.002, PTREND <0.001) with the elevated HbA1c. Multivariate analysis showed that HbA1c (β=0.615, P<0.001), waist circumference (β=0.216, P=0.042), and triglyceride (β=0.121, P=0.048) had a significant association with AUC(FHG). Only HbA1c (β=0.231, P=0.002) and age (β=0.196, P=0.009) was significantly associated with AUC(PPG). CONCLUSION: The data suggested that in Korean T2DM patients, FHG predominantly contributed to overall hyperglycemia at higher HbA1c levels, whereas it contributed to PPG at lower HbA1c levels. It is recommended that certain factors, namely age, degree of glycemic control, obesity, or triglyceride levels, should be considered when prescribing medications for T2DM patients.