Iodixanol compared to iohexol for contrast procedures: A case-matched retrospective cohort study

Background: Previous studies that have attempted to evaluate the effectiveness of an iso-osmolar contrast medium (IOCM) iodixanol compared to a low-osmolar contrast medium (LOCM) for contrast procedures show variable results. Purpose: To evaluate the nephrotoxicity of the IOCM iodixanol compared to the LOCM iohexol. Material and Methods: We performed a retrospective cohort study from April 2004 to March 2006. All contrast procedures with a pre- and post-exposure creatinine value were evaluated for inclusion. Contrast nephropathy (CN) was defined as post-exposure creatinine elevation of 25% or 0.5 mg/dl within 7 days of contrast exposure. Cases of iodixanol exposure were matched to control cases of iohexol exposure (1:1) based on age, sex, presence of diabetes, pre-exposure creatinine value, and type of imaging study performed. We matched 397 cases of iodixanol (IOCM) exposure to 397 cases of iohexol (LOCM) exposure. Cases of iodixanol which could not be matched to controls were not included in the analysis. Results: After adjustment for prior creatinine, medications, contrast iodine load, prior exposure to contrast material, heart failure, and hypertension, use of iodixanol did not significantly alter rates of CN compared to iohexol (OR 0.92, 95% CI 0.57-1.46; P=0.71) or mortality (RR 0.79, 95% CI 0.59-1.06; P=0.12). Conclusion: The use of the IOCM iodixanol was not associated with statistically significant protection against contrast nephropathy or all-cause mortality compared to a matched cohort of patients receiving the LOCM iohexol.