Comparative prognostic performance of early renal biomarkers for major adverse kidney events in severe burn patients.

Abstract

Acute kidney injury (AKI) is a frequent and severe complication in patients with major burns. AKI diagnosis relies on urine output (UO) and serum creatinine (sCr); however, despite being a central therapeutic target during burn resuscitation, the prognostic value of UO remains uncertain. This study evaluated the prognostic performance of early renal biomarkers for renal outcomes in severe burn patients. We conducted a retrospective single-center cohort study including adult patients admitted within 24 h after severe burn injury between 2018 and 2022. AKI was defined according to KDIGO criteria. Early renal parameters sCr, UO, urinary creatinine (uCr), and creatinine clearance (CrCl) were assessed for their predictive performance and association with the primary outcome, Major Adverse Kidney Events at 30 days (MAKE30). Among 106 patients, 47.2% developed AKI within 48 h, and 29.2% experienced MAKE30. AKI was predominantly diagnosed based on UO criteria. During the first 48 h, patients with MAKE30 had lower minimum CrCl (median 54 vs. 136 mL/min, p < 0.001) and higher maximum sCr (97 vs. 68 µmol/L, p < 0.001), while minimum UO did not differ significantly (0.54 vs. 0.92 mL/kg/h, p = 0.11). CrCl was the strongest predictor of MAKE30 (AUC = 0.80), outperforming sCr (AUC = 0.72), UO (AUC = 0.68), and uCr (AUC = 0.63), with an optimal threshold of 42 mL/min. Renal parameters showed weak or no correlation with each other or with hemodynamic variables. A stricter UO threshold (< 0.3 mL/kg/h) was independently associated with MAKE30, whereas the recommended < 0.5 mL/kg/h cutoff was not. Similar findings were observed at 5 days. In severe burn patients, early UO demonstrated limited prognostic value for renal outcomes. CrCl showed superior predictive performance and may improve early renal risk stratification.