title: Intravenous contrast material exposure is not an independent risk factor for dialysis or mortality.
abstract: OBJECTIVE
  To determine the risk of emergent dialysis and short-term mortality following intravenous iodinated contrast material exposure.
  
  
  METHODS
  This single-center retrospective study was HIPAA compliant and institutional review board approved. All contrast material-enhanced (contrast group) and unenhanced (noncontrast group) abdominal, pelvic, and thoracic computed tomography scans from 2000-2010 were identified. Patients in the contrast and noncontrast groups were compared following propensity score-based 1:1 matching to reduce intergroup selection bias. Patients with preexisting diabetes mellitus, congestive heart failure, or chronic or acute renal failure were identified as high-risk patient subgroups for nephrotoxicity. The effects of contrast material exposure on the rate of acute kidney injury ( AKI acute kidney injury ) (serum creatinine level ≥ 0.5 mg/dL [44.2 μmol/L] above baseline within 24-72 hours of exposure) and dialysis or death within 30 days of exposure were determined by using odds ratios ( OR odds ratio s) and covariate-adjusted Cox proportional hazards models. Results were validated with a bootstrapped sensitivity analysis.
  
  
  RESULTS
  The 1:1 matching on the basis of the propensity score yielded a cohort of 21 346 patients (10 673 in the contrast group, 10 673 in the noncontrast group). Within this cohort, the risks of AKI acute kidney injury ( OR odds ratio , 0.94; 95% confidence interval [ CI confidence interval ]: 0.83, 1.07; P = .38), emergent dialysis ( OR odds ratio , 0.96; 95% CI confidence interval : 0.54, 1.60; P = .89), and 30-day mortality (hazard ratio [ HR hazard ratio ], 0.97; 95% CI confidence interval : 0.87, 1.06; P = .45) were not significantly different between the contrast group and the noncontrast group. Although patients who developed AKI acute kidney injury had higher rates of dialysis and mortality, contrast material exposure was not an independent risk factor for either outcome for dialysis ( OR odds ratio , 0.89; 95% CI confidence interval : 0.40, 2.01; P = .78) or for mortality ( HR hazard ratio , 1.03; 95% CI confidence interval : 0.82, 1.32; P = .63), even among patients with compromised renal function or predisposing comorbidities.
  
  
  CONCLUSIONS
  Intravenous contrast material administration was not associated with excess risk of AKI acute kidney injury , dialysis, or death, even among patients with comorbidities reported to predispose them to nephrotoxicity.
authors.affiliation: From the Departments of Radiology (R.J.M., J.S.M., R.P.H., D.F.K., E.E.W.), Health Sciences Research (R.E.C.), and Neurosurgery (D.F.K.), College of Medicine, Mayo Clinic, 200 1st St SW, Rochester, MN 55905; and Department of Radiology, Medical University of South Carolina, Charleston, SC (R.W.K.).
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McDonald
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: McDonald
authors.forename: Rickey E
authors.initials: RE
authors.lastname: Carter
authors.forename: Robert P
authors.initials: RP
authors.lastname: Hartman
authors.forename: Richard W
authors.initials: RW
authors.lastname: Katzberg
authors.forename: David F
authors.initials: DF
authors.lastname: Kallmes
authors.forename: Eric E
authors.initials: EE
authors.lastname: Williamson
mesh_terms: D058186:Acute Kidney Injury / Q000139:chemically induced* / Q000628:therapy*; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects*; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007472:Iohexol / Q000008:administration & dosage* / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D006435:Renal Dialysis; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D014283:Triiodobenzoic Acids / Q000008:administration & dosage* / Q000009:adverse effects*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007472:Iohexol; C044834:iodixanol