Intravenous contrast use and acute kidney injury: a retrospective study of 1,238 inpatients undergoing computed tomography

Objective: To determine the incidence of nephropathy induced by intravenous contrast in hospitalized patients undergoing computed tomography (CT). Materials and Methods: This was a retrospective cohort study involving 1,238 patients who underwent CT with or without intravenous administration of a contrast agent (iopromide). The primary outcome measure was acute kidney injury (AKI), as defined by the traditional criteria - an absolute or relative increase in serum creatinine (SCr) ≥ 0.5 mg/dL or ≥ 25% over baseline, respectively, at 2–3 days after contrast administration—and the newer, Kidney Disease: Improving Global Outcomes (KDIGO) criteria - an absolute or relative increase in SCr ≥ 0.3 mg/dL or ≥ 50% over baseline, respectively, at 2-7 days after contrast administration. Results: The overall incidence of AKI was 11.52% when the KDIGO criteria were applied. Univariate logistic regression demonstrated a significant association between an absolute post-CT increase in SCr ≥ 0.5 mg/dL and AKI, although that association did not retain significance in the multivariate analysis. Multivariate logistic regression initially found an association between an absolute post-CT increase in SCr ≥ 0.3 mg/dL and advanced age, although that association was not maintained after correction. We found no association between AKI and the risk factors evaluated. Conclusion: We identified no criteria for contrast-induced nephropathy after CT; nor did we find AKI to be associated with the classical risk factors. (author)