In search of normoglycaemia in diabetes: controlling postprandial glucose

Abstract

Hyperglycaemia is the diagnostic criterion and a main prognostic parameter in diabetes. Epidemiological and intervention studies have defined the target values for glycaemic control, and there is general consensus that antihyperglycaemic treatment should aim at reducing HbA_1c levels below 7%. In order to achieve this goal it is important that the entire daily glucose profile is reduced. This can be accomplished only by therapies designed to tackle both basal and postprandial hyperglycaemia. However, an increasing bulk of data suggest that postprandial glucose may be even more deleterious that fasting hyperglycaemia in determining the risk for long-term diabetic complications. A strong association has been recognized for a long time between 2 h post-oral glucose tolerance test (OGTT) glucose levels and mortality and cardiovascular disease. Although these data cannot be directly extrapolated to daily life conditions, excessive glucose excursion after the ingestion of a meal seems to be a common phenomenon even in treated diabetic individuals. Rapid-acting insulin analogues, used as the prandial component insulin replacement therapy and short-acting insulin secretagogues, targeting postprandial glucose control, may have a useful new role to play in the management of diabetes mellitus. These interventions have successfully limited postprandial glycaemic exposure, but evidence is still awaited that these outcomes will translate into prognostic benefits. Other components have to be considered in the search for strict glycaemic control. Diabetic patients with similar HbA_1c values may differ in term of glucose stability. Data are available that suggest that patients with larger glucose fluctuation within the day and from day-to-day may be exposed to greater risk of diabetic complications. Therefore, in designing strategies to reduce the burden of diabetic complication both a quantitative effect of hyperglycaemia (fasting, postprandial hyperglycaemia, and HbA_1c) as well as a qualitative component (glucose stability) should be taken into account.