Epidemiology of contrast material-induced nephropathy in the era of hydration

To evaluate the incidence of contrast material-induced nephropathy (CIN) in patients with an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m(2) who received intravenous contrast media and underwent treatment in accordance with current guidelines and to determine risk factors associated with CIN.

The research ethics committee waived the requirement for informed consent for this prospective cohort study. All nonhospitalized patients with an eGFR of less than 60 mL/min/1.73 m(2) were seen at a special outpatient clinic. Patients were stratified for the risk of CIN. They were classified as having high or low risk for CIN on the basis of absolute glomerular filtration rate (Modification of Diet in Renal Disease formula result multiplied by body surface area divided by 1.73 m(2)) and the presence of risk factors. Patients at high risk were hydrated with 1000 mL of isotonic saline before and after contrast material exposure. Serum creatinine level was measured 3-5 days later, and CIN was defined as an increase of 25% of more from the baseline level. Risk factors were recorded and compared between patients with CIN and those without CIN by using forward stepwise multiple logistic regression analysis.

A total of 944 procedures in 747 patients were evaluated. Mean age was 71.3 years ± 10 (standard deviation), and 42.9% of patients were female. In 511 procedures (54.1%), patients were hydrated. CIN developed after 23 procedures (2.4%). No patient needed hemodialysis treatment. Heart failure (odds ratio, 3.0), body mass index (BMI) (odds ratio, 0.9), and repeated contrast material administration (odds ratio, 2.8) were found to be independent predictors of CIN.

Heart failure, low BMI, and repeated contrast material administration were identified as risk factors for CIN under the current treatment strategy. The low incidence of CIN supports the use of hydration as a preventive measure in patients at high risk for CIN.