Post-challenge hyperglycaemia is associated with premature death and macrovascular complications

Unravelling the precise association between cardiovascular disease and Type II (non-insulin-dependent) diabetes mellitus has proved problematic, largely as a result of the confusing variety of diagnostic criteria and methodologies used in previous studies of disease-associated risk. More recently, improved standardization and continuing refinements to risk analyses have begun to clarify the relative importance of individual risk factors for macrovascular complications and progression to cardiovascular disease. The evidence accumulated from several large-scale epidemiological and intervention studies strongly indicates that hyperglycaemia and specifically the post-load hyperglycaemia resulting from postprandial glucose excursions is the main factor associated with increasing the risks of morbidity and mortality in Type II diabetes. The DECODE study has de-emphasized the importance of fasting glucose, in contrast to post-load hyperglycaemia, as the principal measurable determinant of exposure to the risk of cardiovascular disease in Type II diabetes. Similarly, the Diabetes Intervention Study identified mealtime hyperglycaemia as an independent risk factor for myocardial infarction and all-cause mortality, while several other studies have also shown that such mortality is better predicted from post-challenge measurement criteria rather than from fasting-glucose criteria. It is likely that postprandial hyperglycaemia is an independent risk factor for atherosclerosis and is also exerting an atherogenic effect indirectly through the clustering of a number of risk factors for atherosclerosis. Whether the relation between post-load hyperglycaemia and the risk of cardiovascular events is causal is still not known.