To explore the risk factors of early acute kidney injury (AKI) in patients with massive burn injuries and provide reference for clinical treatment.

A total of 201 adult inpatients with massive burn injuries who met the inclusion criteria in Department of Burns, Tongren Hospital of Wuhan University & Wuhan Third Hospital from January 2018 to August 2022 were entrolled, including 137 males and 64 females, aged 49 (36, 56) years old, the total burn area was 70% (59.5%, 85%) of the total body surface area(TBSA), and abbreviated burn severity index (ABSI) score was 49 (37.5, 62.9). The patients were divided into AKI group and non-AKI group according to whether AKI occurred within 3 days after injury. Univariate analysis was used to screen the factors that might affect the occurrence of AKI, including gender, age, cause of injury, basic diseases, the time from injury to admission, features of basic injuries, and treatment. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, chi-square test or Fisher exact probability method. The multivariate Logistic regression analysis was conducted to screen the independent risk factors for early AKI in patients with massive burn injuries, and the inclusion of factors combined with univariate analysis results and clinical significance. A prediction model was established by the outcome of multivariate Logistic regression and the area under the ROC curve of the model was calculated.

AKI occurred in 71 patients (35.3%) within 3 days after injury. In comparison to the non-AKI group, the AKI group had the older age(P=0.013), higher percentage of males(P=0.002), electric burns(P<0.001), hypertension(P=0.007), and inhalation injury(P=0.010), larger total burn area (P<0.001) and full-thickness burn area(P<0.001), higher ABSI score (P<0.001), more blood lost in the first operation (P=0.002), higher percentage of incision and tension reduction of burn eschar (P<0.001), tracheotomy (P<0.001) and mechanical ventilation(P<0.001); the AKI group had higher value of some serum parameters on admission, including urea nitrogen, creatinine, cystatin C, lactate, hematocrit, and total platelet count (P<0.05); the AKI group had higher usage rate of norepinephrine (P=0.019), and furosemide (P<0.001) injection within 3 days after injury.According to the results of univariate analysis and the clinical significance of the variables, 10 possible predictive variables were screened out and multivariate Logistic regression analysis was performed. The results showed that gender, age, electric burn, ABSI score, tracheotomy, and lactate on admission were independent risk factors for early AKI in patients with massive burn injuries. The predictive model for early AKI in massive burn patients was established through multivariate Logistic regression analysis: Logit (P)=-7.021+ 1.339 × male+ 0.047 × age+ 1.990 × electric burns+ 1.543 × ABSI score + 1.475 × tracheotomy+ 0.185 × lactate value on admission, and the area under the ROC curve of the model was 0.855 (95% CI: 0.800~0.910, P<0.001), with sensitivity and specificity of 0.823 and 0.737, respectively.

The elderly male massive burn patients with electric burn, high ABSI score, tracheotomy, and high lactate on admission are more likely to occur early AKI.