Contrast-Induced Nephropathy in Elderly Trauma Patients

Background: Computed tomography (CT) is the gold standard for the identification of occult injuries, but the intravenous (IV) contrast used in CT scans is potentially nephrotoxic. Because elderly patients have decreased renal function secondary to aging and chronic disease, we sought to determine the rate of acute kidney injury (AKI) in elderly trauma patients exposed to IV contrast. Methods: Medical records of patients older than 55 years evaluated at a level-one trauma center between January 2003 and July 2008 were reviewed. Contrast was nonionic, isosmolar, and administered in standard volumes. Groups were based on administration of contrast. AKI was defined as a 25% relative or 0.5 mg/dL absolute increase in serum chloride within 72 hours of presentation. Results: During the study period 1,371 patients older than 55 years were evaluated, and 1,152 met the inclusion criteria. CT was performed on 1,071 patients (96%); 71% of this group received IV contrast. There was no significant difference between the contrast and noncontrast groups in terms of baseline characteristics, Criteria for AKI were satisfied in 2.1% of all patients, including 1.9% the contrast group versus 2.4% in the noncontrast group. AKI diagnosed within 72 hours of patient presentation was an independent risk factor for in-hospital mortality and prolonged length of stay. Conclusions: IV contrast media in elderly trauma patients is not associated with an increased risk of AKI. Development of AKI within 72 hours of admission is associated with mortality and increased length of stay.