Can reducing peaks prevent type 2 diabetes: implication from recent diabetes prevention trials

In recent years, a great deal of discussion has been focused on the role of postprandial hyperglycaemia in terms of development of type 2 diabetes (T2D), coronary heart disease (CHD) and their outcomes in patients with impaired glucose tolerance (IGT). With the incidence of T2D and its projected rise over the next 20 years, both the understanding of the pathophysiology of postprandial hyperglycaemia before development of frank T2D and the efficacy of interventions directed at lowering the postprandial glycaemic load to prevent the development of T2D have gained public health importance worldwide. Clinical trials have demonstrated that postprandial hyperglycaemia carries not only pathophysiological but also prognostic importance with regard to the quality of glycaemic control and forecasts the development of T2D, its complications, and patient mortality. The Diabetes Prevention Program randomised trial has shown that reducing postprandial hyperglycaemic peaks by a combined program of weight loss, improvement of diet, increase of physical exercise and smoking cessation lowers the risk for development of T2D by 58% compared with placebo and is equally beneficial to all patients, regardless of ethnicity, BMI, sex or level of glycaemia. Treatment with metformin was less effective than lifestyle modifications, resulting in an average reduction of risk of T2D of 31% compared with placebo. Postprandial hyperglycaemia plays a central role in the development of CHD in subjects with IGT, and reducing postprandial plasma glucose levels with lifestyle modifications in order to prevent T2D may also extend its benefits towards lower incidences of CHD and CHD-related mortality.