New Study Questions Whether Contrast Agents Cause Acute Kidney Damage

Many physicians have long held the belief that the use of intravenous (IV) contrast agents for computed tomography (CT) imaging can cause acute kidney injury. New research questions the validity of the causal association between the two.

The findings from two tandem studies are published online January 29, 2013, in the journal Radiology. The first study examined all previous research that compared patients who did or did not receive contrast agents, while the second paper represented a new retrospective study of over 100,000 CT scans performed at the Mayo Clinic (Rochester, MN, USA) from 2000 to 2010, the largest published study up to now assessing the effect of contrast-enhanced imaging on renal function. In the retrospective study, researchers performed statistical analyses to examine the causality and mimic a randomized controlled trial to for optimizing the correlation of patients who received contrast agents to those patients who did not. These methods had not been performed in any earlier research of renal function following contrast administration.

“These studies have significant clinical ramifications with regard to who is eligible to receive contrast media during CT exams,” stated lead coauthor Bob McDonald, MD, PhD, a radiologist at Mayo Clinic. “Despite limited clinical evidence, contrast is commonly withheld during CT exams of individuals with even modest renal impairment due to concern for kidney injury, often at the expense of diagnostic accuracy of the exam. Our goal for these studies was to provide better evidence regarding the true incidence of renal injury following intravenous contrast administration and better define the ‘at-risk’ patient population.”

In both studies, Mayo Clinic researchers discovered that patients who received intravenous contrast agents and those who did not had a similar risk of developing acute kidney injury. “Our findings suggest that, if contrast-induced nephropathy exists at all, it is likely rare and cannot be easily identified from unrelated causes of renal injury,” said lead coauthor Jennifer McDonald, PhD, a radiology associate at Mayo Clinic. “Hopefully our findings can promote additional research to help redefine the safety window of contrast media and in turn, improve patient care through more frequent use of appropriate clinical imaging.”

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