Analysis of Risk Factors for Early Acute Kidney Injury in Critically Ill Burn Patients

Abstract

Acute kidney injury (AKI) is a common early complication in critically ill burn patients, but its risk factors remain incompletely understood. This study aimed to identify independent risk factors for early AKI in this population. A retrospective study enrolled 98 critically ill burn patients admitted to the participating medical center from January 2016 to September 2025. Patients were divided into AKI and non-AKI groups based on AKI occurrence within 3 days post-injury. Admission data (demographics, laboratory parameters, inflammatory indices) were analyzed. Independent risk factors were identified via univariate analysis, multicollinearity diagnosis, and multivariate logistic regression; a prediction model was constructed and evaluated using ROC curve analysis. The incidence of early AKI in critically ill burn patients was 28.6%. The multivariate logistic regression analysis revealed that blood urea nitrogen (BUN; OR = 1.519; 95% CI: 1.042 ~ 2.214; p = 0.030), cystatin C (CYS; OR = 12.142; 95% CI: 1.240 ~ 118.858; p = 0.032), and D-dimer (OR = 1.136; 95% CI: 1.006 ~ 1.283; p = 0.040) levels were independent risk factors for early AKI. The prediction model equation was Logit(P) = -9.159 + 0.418 × BUN (mmol/L) + 2.497 × CYS (mg/L) + 0.127 × D-dimer (mg/L). The area under the ROC curve (AUC) for this model was 0.887 (95% CI: 0.816 ~ 0.958; p < 0.001), and the optimal cut-off value was determined by the maximum Youden index, which was 0.235. According to the prediction equation, a calculated probability p ≥ .235 indicates a high risk of early AKI. Elevated BUN, CYS, and D-dimer levels increase early AKI risk in critically ill burn patients.