Background fluctuation of kidney function versus contrast-induced nephrotoxicity

Area of Science:

• Nephrology
• Radiology
• Medical Imaging

Background:

• The incidence of contrast-induced acute kidney injury (AKI) varies significantly.
• Few studies have quantified background kidney function fluctuations in patients receiving iodinated contrast media.
• Understanding AKI incidence requires comparison with non-contrast imaging.

Purpose of the Study:

• To retrospectively compare AKI incidence in patients undergoing CT with low-osmolar (iohexol) or isoosmolar (iodixanol) contrast media versus CT without contrast.
• To assess the actual risk of contrast media in AKI development.

Main Methods:

• Evaluated creatinine and estimated glomerular filtration rate (eGFR) in 11,588 patients.
• Defined AKI as a 0.5 mg/dL creatinine increase or 25% eGFR decrease within 3 days post-CT.
• Compared AKI rates across contrast and non-contrast groups, stratified by baseline kidney function.

Main Results:

• AKI incidence increased with baseline creatinine levels across all groups.
• No significant difference in AKI incidence between isoosmolar contrast and control groups.
• Low-osmolar contrast showed similar AKI incidence to controls up to creatinine 1.8 mg/dL; higher incidence above this level.

Conclusions:

• A high incidence of AKI was observed in the control group (unenhanced CT).
• Creatinine elevation in the isoosmolar contrast group was similar to controls across all baseline creatinine and CKD stages.
• The additional risk of AKI from contrast media (contrast-induced nephrotoxicity) may be overestimated; background factors likely contribute significantly.