No association between contrast use and AKI seen in critically ill patients with normal kidney function

Acute kidney injury (AKI) was significantly associated with clinical factors, such as sepsis, metabolic disorders, and severity of illness, but not the use of IV contrast, according to a propensity-matched analysis of ICU patients.

The risk of acute kidney injury (AKI) was not significantly increased in ICU patients with normal kidney function who received contrast compared to similar patients who did not receive it, a recent study found.

The retrospective observational study included ICU patients from a six-hospital health system in South Florida. Patients who had received low osmolar radiocontrast media were propensity matched (on baseline characteristics, admission diagnoses, comorbidities, and severity of illness) to unexposed controls to create 2,306 patient pairs. The primary outcome was AKI, defined as initial onset (stage 1) or increased severity, determined from serum creatinine. Results were published by CHEST on Oct. 25.

Patients who received contrast had an AKI risk of 19.3% compared to 18.0% in those who didn't, an insignificant difference (P=0.273). The study also found no association between contrast use and the pattern of AKI onset and recovery. Patients who developed AKI did have a significantly increased risk of hospital mortality (18.0% vs. 3.6%; P<0.001), but the risk ratio did not vary when stratified by contrast use. Multivariable regression analysis found factors other than the receipt of contrast were associated with AKI, including sepsis, metabolic disorders, diabetes, history of renal disease, and severity of illness.

Several other studies have also failed to find an association between contrast and AKI in critically ill patients, the study authors noted. Strengths of this study include its large, diverse sample of patients who were well matched between those with and without contrast exposure. Limitations include potential effects of unmeasured confounders and lack of data on fluid intake.

Based on the results, the authors concluded that contrast does not increase AKI risk in critically ill patients with normal kidney function enough that its use should be avoided when otherwise indicated. The study “adds to a growing body of evidence that the risk of AKI in relation to administration of contrast media has been overstated leading to unnecessary guidelines limiting its use and diverting the focus of preventive measures away from more significant susceptibilities,” the authors said.