Contrast material-induced nephrotoxicity and intravenous low-osmolality iodinated contrast material.
OBJECTIVE
To determine whether intravenous low-osmolality iodinated contrast material is associated with post-computed tomography (CT) acute kidney injury (AKI).


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 in adult inpatients with sufficient serum creatinine (SCr) data were identified. A one-to-one propensity-matched matched cohort analysis with multivariate analysis of effects was performed with post-CT AKI as the primary outcome measure (10,121 unenhanced and 10,121 intravenous contrast-enhanced CT examinations in 20,242 patients). Propensity matching was performed with respect to likelihood of patient receiving intravenous contrast material (36 tested covariates). The primary endpoint was post-CT AKI by using Acute Kidney Injury Network SCr criteria; the secondary endpoint was post-CT AKI by using traditional SCr criteria for contrast material-induced nephrotoxicity (CIN; SCr increase ≥0.5 mg/dL [44.20 μmol/L] or ≥25%). Multivariate subgroup threshold analysis was performed (SCr <1.5 [<132.60 μmol/L]; ≥1.5 to ≥2.0 mg/dL [≥132.60 to ≥176.80 μmol/L]) and adjusted for assigned propensity scores.


RESULTS
Intravenous low-osmolality iodinated contrast material had a significant effect on the development of post-CT AKI for patients with pre-CT SCr levels of 1.6 mg/dL (141.44 μmol/L) or greater (odds ratio, 1.45; 95% confidence interval [CI]: 1.11, 1.89;P = .007). This effect strengthened as pre-CT SCr increased. Patients with stable SCr less than 1.5 mg/dL (132.60 μmol/L) were not at risk for developing CIN (P = .25, power > 95%). Both endpoints demonstrated similar results (eg, SCr ≥1.6 mg/dL [141.44 μmol/L] by using traditional CIN criteria: odds ratio, 1.64; 95% CI: 1.18, 2.28; P = .003). Post-CT AKI was prevalent in both the unenhanced and contrast-enhanced CT subgroups, and it increased with increases in pre-CT SCr. Many risk factors contributed to development of post-CT AKI, regardless of iodinated contrast material.


CONCLUSIONS
Intravenous low-osmolality iodinated contrast material is a nephrotoxic risk factor, but not in patients with a stable SCr level less than 1.5 mg/dL. Many factors other than contrast material can affect post-CT AKI rates.
Department of Radiology, University of Michigan Health System, 1500 E Medical Center Dr, B2-A209P, Ann Arbor, MI 48103, USA. matdaven@umich.edu
Matthew S
MS
Davenport
Shokoufeh
S
Khalatbari
Jonathan R
JR
Dillman
Richard H
RH
Cohan
Elaine M
EM
Caoili
James H
JH
Ellis
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003287:Contrast Media / Q000009:adverse effects* / Q000737:chemistry; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007472:Iohexol / Q000009:adverse effects / Q000031:analogs & derivatives; D007479:Iopamidol / Q000009:adverse effects; D007674:Kidney Diseases / Q000139:chemically induced*; D007677:Kidney Function Tests; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D057216:Propensity Score; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D014283:Triiodobenzoic Acids / Q000009:adverse effects
D003287:Contrast Media; D014283:Triiodobenzoic Acids; D007472:Iohexol; C038192:iopromide; C044834:iodixanol; D007479:Iopamidol