Kuhn MJ et al. (2008) The PREDICT study: a randomized double-blind comparison of contrast-induced nephropathy after low- or isoosmolar contrast agent exposure. AJR Am J Roentgenol 191: 151–157

Low-osmolar contrast agents are associated with a lower risk of contrast-induced nephropathy (CIN) than high-osmolar contrast media among patients with pre-existing renal dysfunction. The recently reported PREDICT (Patients with Renal Impairment and Diabetes Undergoing Computed Tomography) study investigated whether iso-osmolar contrast agents are associated with a further decrease in the risk of CIN.

The investigators randomly allocated 263 patients with diabetes and moderate to severe chronic kidney disease, who were scheduled to undergo contrast-enhanced multidetector CT, to receive either a low-osmolar (iopamidol 370; n = 132) or iso-osmolar (iodixanol 320; n = 131) intravenous contrast agent. Serum creatinine levels were obtained before and 48–72 h after contrast agent administration.

Baseline renal function was similar in the two groups. Among the 248 evaluable patients, the incidence of CIN—defined as an increase in serum creatinine level of ≥25%—was statistically similar in patients who received iopamidol 370 and those who received iodixanol 320 (5.6% vs 4.9%). Mean increase in serum creatinine level from baseline was 3.5 µmol/l in both groups. Subgroup analyses of high-risk patients (i.e. those with poorest baseline renal function and those given the highest doses of contrast agent) confirmed that the incidence of CIN was similar between groups.

The authors conclude that the risk of CIN is low in patients with diabetes and moderate to severe renal impairment who receive low-osmolar or iso-osmolar intravenous contrast medium, and that these two types of contrast agents confer a similar risk.