Objectives This study was undertaken to compare the renal safety of iso-osmolar iodixanol vs. low-osmolar iopromide in patients with chronic kidney disease (CKD) undergoing coronary angiography and /or intervention.BackgroundWith the growing number of contrast-enhanced procedures being performed for coronary artery disease management, the safety and efficacy of iodinated contrast media (CM) have come under increased scrutiny. Contrast-induced nephropathy (CIN) is a common cause of in-hospital renal failure. A prior meta-analysis and studies was conflicting about the safety of iodixanol (IOCM) compared with iopromide (LOCM) in reduce the incidence of CIN in patients with chronic kidney disease (CKD) undergoing coronary interventions.Methods One hundred ten patients with CKD (eGFR ≤ 60 mL/min/1.73m2) were randomized in 1:1 fashion to receive either iso-osmolar contrast agent (iodixanol =55) or low-osmolar contrast agent (iopromide =55) with proper hydration. Serum creatinine levels were measured at baseline and 48–72 hours after contrast administration. Contrast-induced nephropathy (CIN) was defined as an increase in serum creatinine (SCr) ≥25% or 0.5 mg/dL within 72 hr of CM administration. Results The overall incidence of CIN expressed as a relative ≥ 25% increase in SCr was significantly lower in iodixanol group than iopromide group (7patients (12.7%) vs. 17 patients(29.1%), P= 0.035). Similarly when expressed as an absolute ≥0.5 mg/dL increase in SCr the incidence of CIN was significantly lower in patients who received iodixanol: 8 patients (14.5%) compared with those who received iopromide: 19 patients (34.5%); P= 0.015. Among all variables in the study, female gender (HR=0.29; 95% confidence interval 0.1 to 0.7, P=0.008), use of iopromide (HR=3.59; confidence interval 1.3 to 9.3, P=0.008) and DM appeared to be associated with higher risk of CIN by >25% and ≥0.5 mg increase SCr from baseline.Conclusions In patients with impaired renal function undergoing coronary catheterization, use of iso-osmolar contrast medium, iodixanol is associated with lower risk of contrast induced nephropathy than the low-osmolar contrast medium, iopromide. Among many clinical and procedure related variables, only female gender and use of contrast medium iopromide are associated with increased risk of contrast induced nephropathy.