Diabetes Mellitus

Abstract

Diabetes mellitus (diabetes Greek, pass through/siphon; mellitus Latin, honey sweet) is a heterogeneous, multifactorial metabolic disorder characterized by chronic hyperglycemia. This is in part because insulin secretion is insufficient to maintain blood glucose levels in a physiological range [1]. On the one hand, diabetes can be diagnosed based on classical symptoms, i.e., polyuria (excessive production of urine) and polydipsia (excessive fluid intake) due to osmotic diuresis following glucosuria. The presence of glucose in urine is caused by blood glucose levels exceeding the capacity of renal tubular sodium-glucose linked transporters (SGLTs) to reabsorb glucose from the primary urine. On the other hand, the World Health Organization (WHO) criteria define diabetes either as a fasting blood glucose level at or above 7 mmol/l or as a level at or above 11.1 mmol/l 2 h post glucose challenge during an oral glucose tolerance test (2-h plasma glucose). The WHO further describes criteria of a prediabetes that comes with a strongly increased risk to develop diabetes. These include an impaired fasting blood glucose between 6.1 mmol/l and 6.9 mmol/l. In addition, an impaired glucose tolerance as indicated by a 2-h plasma glucose between 7.8 mmol/l and 11 mmol/l or glycated hemoglobin between 5.7 and 6.4 % points to prediabetes [2].