Hyperglycemia, hypoglycemia and glycemic variability in the elderly: a fatal triad?

Diabetes mellitus is one of the most important causes of cardiovascular morbidity and mortality; the incidence of chronic complications of diabetes appears to be closely related to the degree of hyperglycaemia. However, results of clinical trials showed that intensive treatment of hyperglycaemia prevents microvascular complications, but has little or no effect on the incidence of cardiovascular events. Different hypoglycaemic drugs show different effects on cardiovascular risk. However, those trials have shown a neutral effect on cardiovascular mortality. This paradoxical result could be explained with the frequent use, in the past, of glucose-lowering agents capable of increasing the risk of hypoglicemia, glycemic variability and weight gain. In conclusion, an adequate glycemic control, in particular in elderly patients, should be achieved, whenever possible, using agents not inducing hypogycemia, glucose fluctuations, and weight gain. In fact, hypoglycaemia and glucose variability should be considered as independent cardiovascular risk factors to a similar extent to hyperglycemia. In this article, the author will review literature supporting the hypothesis that hyperglycemia, hypoglycaemia and glycemic variability are a fatal triad capable of increasing morbidity and mortality in patients with diabetes mellitus.