Background

Acute kidney injury (AKI) is a common complication in critically ill patients with cancer. The RIFLE criteria define three levels of AKI based on the percent increase in serum creatinine (Scr) from baseline: risk (≥50%), injury (≥100%), and failure (≥200% or requiring dialysis). The utility of the RIFLE criteria in critically ill patients with cancer is not known.

Objective

To examine the incidence, outcomes, and costs associated with AKI in critically ill patients with cancer.

Methods

We retrospectively analyzed all patients admitted to a single-center ICU over a 13-month period with a baseline Scr ≤1.5 mg/dL (n = 2,398). Kaplan-Meier estimates for survival by RIFLE category were calculated. Logistic regression was used to determine the association of AKI on 60-day mortality. A log-linear regression model was used for economic analysis. Costs were assessed by hospital charges from the provider's perspective.

Results

For the risk, injury, and failure categories of AKI, incidence rates were 6%, 2.8%, and 3.7%; 60-day survival estimates were 62%, 45%, and 14%; and adjusted odds ratios for 60-day mortality were 2.3, 3, and 14.3, respectively (P ≤ 0.001 compared to patients without AKI). Hematologic malignancy and hematopoietic cell transplant were not associated with mortality in the adjusted analysis. Hospital cost increased by 0.16% per 1% increase in creatinine and by 21% for patients requiring dialysis.

Limitations

Retrospective analysis. Single-center study. No adjustment by cost-to-charge ratios.

Conclusions

AKI is associated with higher mortality and costs in critically ill patients with cancer.