Contribution of postprandial glucose to excess hyperglycaemia in Asian type 2 diabetic patients using continuous glucose monitoring

Background: Previous studies examining the contributions of fasting glucose (FG) and postprandial glucose (PPG) to glycated haemoglobin ($\hbox{HbA}_{{\rm 1c}}$ ) have yielded conflicting results. We aimed to clarify the contributions of PPG to hyperglycaemia in Asian type 2 diabetic patients using continuous glucose monitoring.Methods: Continuous glucose monitoring was conducted in 121 non‐insulin‐using type 2 diabetic outpatients, who were divided into five groups according to quintiles of $\hbox{HbA}_{{\rm 1c}}$ (ranging from 5.7 to 12.7%). Glucose area under the curve (AUC) above a glucose value of 5.5 mmol/L 24 or 4 h after meals was defined as $\hbox{AUC}_{{\rm total}}$ . Glucose AUC above FG or preprandial glucose levels was defined as $\hbox{AUC}_{{\rm PPG}}$ . The contribution of PPG to hyperglycaemia was calculated as ($\hbox{AUC}_{{\rm PPG}}$ /$\hbox{AUC}_{{\rm total}}$ ) × 100%. The contribution of FG or preprandial glucose was calculated as [($\hbox{AUC}_{{\rm total}} -$ $\hbox{AUC}_{{\rm PPG}}$ )/$\hbox{AUC}_{{\rm total}}$ ] × 100%.Results: The contribution of PPG to either 24‐h hyperglycaemia or 4‐h hyperglycaemia after meals was significantly higher than FG and preprandial glucose in the lowest quintile of $\hbox{HbA}_{{\rm 1c}}$ (both p < 0.001). However, no difference was observed in the other four quintiles. Peak PPG and glucose excursions were higher after breakfast than those after lunch and dinner (p < 0.01 for all comparisons).Conclusions: In Asian patients with type 2 diabetes, PPG 24 and 4 h after meals was a predominant contributor to excess hyperglycaemia in well‐controlled patients and was equally important as FG or preprandial glucose in moderately to poorly controlled patients with mean $\hbox{HbA}_{{\rm 1c}}$ up to 10%. Copyright © 2010 John Wiley & Sons, Ltd.