Body surface area is a predictor of 90-day all-cause mortality in critically ill patients with acute kidney injury.

OBJECTIVE: To clarify the prognosis effect between body surface area (BSA) and patients with acute kidney injury (AKI), we attempted to analyze the association between BSA and 90-day all-cause mortality in critically ill patients with AKI.

METHODS: Clinical data of 9195 critically ill patients with AKI were retrieved from the Medical Information Mart for Intensive Care III database were then retrospectively analyzed. BSA were calculated using the Mosteller formula. We analyzed the correlation between BSA and 90-day all-cause mortality in critically ill patients with AKI based on Kaplan-Meier curve analysis and adjusted Cox regression model.

RESULTS: Of the 9195 critically ill patients with AKI, there were 3778 (41.1%) female patients and 2001 90-day all-cause deaths (female: 22.2%, male: 21.5%). Kaplan-Meier curve analysis revealed that a lower body surface area indicated a higher 90-day all-cause mortality in both male and female patients with AKI (log-rank P < 0.001). Cox regression model showed that a higher BSA was independently correlated with a lower 90-day all-cause mortality (female: hazard ratio=0.657, 95% confidence interval: 0.550-0.784, P < 0.001; male: hazard ratio=0.655, 95% confidence interval: 0.565-0.760, P < 0.001).

CONCLUSIONS: BSA was negatively correlated with 90-day all-cause mortality in critically ill patients with AKI. BSA can therefore be used as a prognostic indicator for poor outcomes in critically ill patients with AKI.