More Evidence Against Nephropathy Induced by Intravenous Contrast

In studies published several years ago by researchers at Mayo Clinic Rochester, intravenous iodinated contrast use in computed tomography (CT) scanning was not associated with acute kidney injury (AKI; NEJM JW Gen Med May 1 2014 and Radiology 2014; 271:65; NEJM JW Gen Med Dec 15 2014 and Radiology 2014; 273:714). Now, this team has performed a retrospective study of data from a new cohort of 5758 adults with chronic kidney disease (CKD; stages 1−5) who underwent either noncontrast CT or iodixanol-enhanced contrast CT and who had pre- and post-CT serum creatinine measurements. The researchers chose to confine this cohort to recipients of iodixanol, the iso-osmolar agent that generally was being used for patients perceived to be at high risk for postcontrast AKI.

Propensity-score matching yielded contrast-exposed and noncontrast groups (≈1500 patients in each group) who were statistically very similar on a broad range of clinical and demographic variables, including baseline renal function. Contrast exposure was not associated with excess AKI incidence, need for dialysis, or mortality — regardless of baseline renal function. Although relatively few patients with CKD stages 4 and 5 could be propensity-matched (76 contrast-exposed patients vs. 198 noncontrast patients), no hint of contrast-associated worsening of renal function was apparent even in these patients with advanced renal disease. An additional analysis of data from Mayo Clinic sites in Florida and Arizona yielded similar findings.