The goal in the management of patients with type 2 diabetes is to control fasting plasma glucose and glycosylated hemoglobin (HbA1c) levels. In patients with well-controlled diabetes (HbA1c <7%, or within 1% of normal) or glucose intolerance (fasting plasma glucose level <126 mg/dL, and a 2-hour plasma glucose of 140 to 200 mg/dL after 75 g of oral glucose), postprandial hyperglycemia has a greater effect on HbA1c than fasting glucose levels. Jovanovic recently reported that the postprandial glucose level at 1 hour is the best predictor of HbA1c in patients with well-controlled type 2 diabetes mellitus. In addition, a French study of patients with type 2 diabetes showed that glucose concentrations at 2 and 5 hours after a meal were better predictors of the HbA1c than prebreakfast or prelunch values. Therefore, in patients with elevated HbA1c, the postprandial plasma glucose levels may play a disproportionate role in the genesis of both microvascular and macrovascular complications of diabetes.
The recent change in plasma glucose threshold for the diagnosis of diabetes was based on evidence such as that from the United Kingdom Prospective Diabetes Study, which showed that 50% of patients with type 2 diabetes already had one or more chronic complications by the time it was diagnosed. The standard for diagnosis is still a plasma glucose level >200 mg/dL at 2 hours after a 75-g glucose load. Postprandial levels >200 mg/dL are seen in 97% of patients with a fasting plasma glucose value of 126 mg/dL. In addition, 52% of patients with fasting plasma glucose <126 mg/dL still have postprandial levels >200 mg/dL. Therefore, patients with fasting glucose levels between 110 and 126 mg/dL should undergo a 2-hour, 75-g glucose challenge to assess their postprandial glucose levels, since early detection and treatment can delay or prevent the onset of complications.
South Med J. 2001;94(8) © 2001 Lippincott Williams & Wilkins
Cite this: Importance of Postprandial Glucose Control - Medscape - Aug 01, 2001.