Background: previous studies examining the contributions of fasting glucose (FG) and postprandial glucose (PPG) to glycated haemoglobin (HbA(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 HbA(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 AUC(total). Glucose AUC above FG or preprandial glucose levels was defined as AUC(PPG). The contribution of PPG to hyperglycaemia was calculated as (AUC(PPG)/AUC(total) × 100%. The contribution of FG or preprandial glucose was calculated as [(AUC(total) - AUC(PPG))/AUC(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 HbA(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 HbA(1c) up to 10%.
2010 John Wiley & Sons, Ltd.