Is standard hydration a protective measure against Contrast-induced nephropathy?

Contrast-induced nephropathy (CIN) is an iatrogenic disorder, resulting from procedures requiring the intravascular administration of iodinated contrast media. It is associated with increased morbidity, mortality, and high costs. CIN remains the third most common cause of hospital-acquired kidney failure. We aimed at determining CIN risk factors and the preventive effect of N/S hydration in patients undergoing coronary angiography. This cross-sectional study was performed over a period of 48 months from 2008 to 2012. Totally, 2220 patients with an indication for coronary angiography were randomly divided into two groups: group 1 with 816 patients who received 1-2 mg/kg of normal saline infusion for 6 hours before the procedure and group 2 with 1404 patients without any intervention. Serum creatinine was checked before and 48 hours after selective coronary angiography. Significant rise in initial serum creatinine level was defined as 25% or 0.5 mg/dl. Mean age of the patients was 58.20±11.222 years. Mean serum Cr levels before and after angiography were 1.05±0.66 mg/dl (min: 0.05 mg/dl, max: 2.1.1 mg/dl) and 1.13±0.78 mg/dl (min:0.05 mg/dl, max: 2.4 mg/dl), respectively. Mean contrast media volumes in group 1 and 2 were 47.30±27.69 cc versus 42.20±22.06 cc (p≤0.001). The prevalence of CIN in group 1 was 23.8% versus 23.5% in group 2. We did not find any preventive effect for standard hydration in the studied patients except for cases with diabetes mellitus, dyslipidemia, smoking, underlying renal disease (CKD), male gender, age > 65 years, and serum hemoglobin ≥14mg/dl