Iodinated contrast material, long considered a prime suspect for nephrotoxicity, may be less risky than previously assumed. In a large retrospective study, researchers evaluated patient records for the frequency and magnitude of serum creatinine changes in a control group of patients who hadn't received iodinated contrast material. They then compared those findings with previously published studies that found a link between contrast media, serum creatinine levels, and nephropathy.

Of the 32,161 patients who didn't receive contrast material, more than half had a serum creatinine change of at least 25%. Analyzing the data, researchers concluded that creatinine levels increased in patients who didn't receive I.V. iodinated contrast material as often as they did in published studies of patients who received I.V. iodinated contrast material.

The changes in creatinine levels were "undoubtedly caused by the entire range of conditions, treatments, and laboratory variations" that can alter creatinine levels, said Jeffrey H. Newhouse, MD, lead study author. "We don't claim that I.V. contrast material never induces nephropathy, but it may do so less frequently and severely than previously thought."

Sources: Newhouse JH, et al., Frequency of serum creatinine changes in the absence of iodinated contrast material: Implications for studies of contrast nephrotoxicity, American Journal of Roentgenology, August 2008; Kidney damage caused by iodinated contrast material thought to be overestimated, Newswise, July 16, 2008.