Contrast material-induced nephrotoxicity and intravenous low-osmolality iodinated contrast material: risk stratification by using estimated glomerular filtration rate.

PURPOSE: To determine the effect of intravenous (IV) low-osmolality iodinated contrast material (LOCM) on the development of post-computed tomography (CT) acute kidney injury (AKI), stratified by pre-CT estimated glomerular filtration rate (eGFR), in patients with stable renal function.

MATERIALS AND METHODS: Institutional review board approval was obtained and patient consent waived for this HIPAA-compliant, retrospective study. CT examinations performed over a 10-year period on unique adult inpatients with sufficient serum creatinine (SCr) data and stable renal function (difference between baseline and pre-CT SCr within 0.3 mg/dL and 50% of baseline) were identified. A 1:1 propensity score matched cohort analysis with multivariate analysis of effects was performed with post-CT AKI as the primary outcome measure (8826 nonenhanced and 8826 IV contrast agent-enhanced CT studies in 17 652 patients). Propensity matching was performed with respect to likelihood of receiving IV contrast material (19 tested covariates). Post-CT AKI with Acute Kidney Injury Network SCr criteria was the primary endpoint. A stepwise multivariate conditional logistic regression model was performed to identify the effect of IV LOCM on post-CT AKI.

RESULTS: After 1:1 propensity matching, IV LOCM had a significant effect on the development of post-CT AKI (P = .04). This risk increased with decreases in pre-CT eGFR (≥ 60 mL/min/1.73 m(2): odds ratio, 1.00; 95% confidence interval: 0.86, 1.16; 45-59 mL/min/1.73 m(2): odds ratio, 1.06; 95% confidence interval: 0.82, 1.38; 30-44 mL/min/1.73 m(2): odds ratio, 1.40; 95% confidence interval: 1.00, 1.97; <30 mL/min/1.73 m(2): odds ratio, 2.96; 95% confidence interval: 1.22, 7.17).

CONCLUSION: IV LOCM is a nephrotoxic risk factor in patients with a stable eGFR less than 30 mL/min/1.73 m(2), with a trend toward significance at 30-44 mL/min/1.73 m(2). IV LOCM does not appear to be a nephrotoxic risk factor in patients with a pre-CT eGFR of 45 mL/min/1.73 m(2) or greater.