Contribution of postprandial glucose to chronic hyperglycaemia: from the "glucose triad" to the trilogy of "sevens"

Abstract

Even though fasting and postprandial glucose are both contributors to the overall hyperglycaemia as observed in patients with type 2 diabetes, their respective contributions are varying with the degree of diabetic control. The contribution of postprandial glucose is predominant in patients with satisfactory control of diabetes (HbAlc < 7.3%) whereas the contribution of fasting glucose increases progressively with worsening diabetes. As a consequence an overall picture of the diabetic control should normally be based on the assessment of the "glucose triad" with its three components: HbAlc which integrates the diabetic control over a 3-month period, fasting and postprandial glucose. The two later are good indicators of the glycaemic regulation over the two main physiological periods of daytime: the fasting and postprandial states. Postprandial glucose concentrations should be more particularly tested at mid-morning time since in most patients this period corresponds to the highest glucose concentrations of daytime. However postprandial measurements at 2-h after lunch provide an evaluation of the overall diabetic control since we have demonstrated that glucose concentrations < 7 mmol/L at this time point are excellent predictors of HbAlc levels < 7% (specificity 2 90%). Therefore, in order to simplify the work of health care providers the "glucose triad" concept can be translated into the trilogy of "sevens": HbA1c goals < 7% and postprandial glucose targets < 7 mmol/L 2-h after lunch, both for assessing a satisfactory diabetic control, and fasting glucose < 7 mmol/L for defining the non-diabetic state.