Costs and Outcomes of Acute Kidney Injury in Critically Ill Patients with Cancer

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.