**4.2 Diabetes mellitus**

Diabetic patients represent a very important proportion of those undergoing contrast exposures due not only to the prevalence of diabetes in the general population but also the ability of the disease to cause a wide spectrum of diseases which require radiological procedures using contrast media. The incidence of CIN in diabetic patients varies from 5.7 to 29.4% [26]. Importantly, in diabetic patients with preserved renal function and without other risk factors, the rates of CIN are approximately equal to those of a nondiabetic population [27], while clinically important CIN mostly happens in a group of diabetics with preexisting renal impairment [27].
