Value of renal injury marker protein in early diagnosis of acute kidney injury in burn patients with delayed resuscitation

Objective To explore the value of renal injury marker protein in early diagnosis of acute kidney injury (AKI) in burn patients with delayed resuscitation. Methods The retrospective case-control research was conducted. Forty-three burn patients with delayed resuscitation (27 males and 16 females, with age of 18-75 (35±3) years)who were admitted to Zhengzhou First People′s Hospital from May 2018 to May 2020 met the inclusion criteria. The patients were divided into AKI group with 23 patients and non-AKI group with 20 patients according to whether AKI occurred within 7 days after burns. The gender, age, deep partial-thickness burn area, full-thickness burn area, and acute physiology and chronic health evaluation Ⅱ of patients were compared between the two groups.The fluid supplement volume and serum creatinine at 12, 24, and 48 h after burn, serum albumin/fibrinogen ratio (AFR), urinary heat shock protein 70 (HSP70), tissue inhibitor of metalloproteinase-2 (TIMP-2)×insulin-like growth factor binding protein 7 (IGFBP-7), and neutrophil gelatinase associated lipocalin (NGAL)at 12, 24, 48, 72, 120, and 168 h after burn were detected.Data were statistically analyzed with Mann-Whitney

test, analysis of variance for repeated measurement, independent-samples

test, chi-square test and Bonferroni correction. The independent variable to predict the occurrence of AKI was screened by multi-factor logistic regression analysis. The receiver′s operating characteristic curve was drawn for predicting the occurrence of AKI in burn delayed resuscitation patients, and the area under the curve (AUC), the best threshold, and the sensitivity and specificity under the best threshold were calculated. Results The gender, age, deep partial-thickness burn area, full-thickness burn area, acute physiology and chronic health evaluation Ⅱ of patients in two groups were similar (

²=1.98,

=1.98, 1.99, 1.99, 1.99,

>0.05). The fluid supplement volume of patients in AKI group at 24 and 48 h after burn was significantly less than that in non-AKI group (

=15.37, 6.51,

<0.01). The serum creatinine of patients in AKI group at 12, 24, and 48 h after burn was significantly higher than that in non-AKI group (

=2.16, 5.62, 6.72,

<0.01). The serum AFR of patients in AKI group at 12, 24, 48, 72, 120, and 168 h after burn was significantly lower than that in non-AKI group (

=16.14, 35.35, 19.60, 20.47, 30.20, 20.17,

<0.01). The levels of urinary HSP70 of patients in AKI group at 12, 24, 48, 72, 120, and 168 h after burn were (6.89±0.87), (6.42±0.73), (5.81±0.72), (5.17±0.56), (4.63±0.51), (3.89±0.51) μg/L, which were significantly higher than (3.89±0.75), (3.57±0.63), (2.66±0.41), (1.83±0.35), (1.48±0.19), (1.28±0.19) μg/L in non-AKI group (

=12.00, 13.61, 17.39, 22.98, 26.34, 21.59,

<0.01). Urinary TIMP-2×IGFBP-7 and NGAL of patients in AKI group at 12, 24, 48, 72, 120, 168 h after burn were significantly higher than those in non-AKI group (

=26.94, 101.11, 35.50, 66.89, 17.34, 14.30, 14.00, 13.78, 12.32, 14.80, 21.36, 22.62,

<0.01). Urinary HSP70 and serum AFR at 12 h after burn, urinary TIMP-2×IGFBP-7 and NGAL at 24 h after burn were included into multi-factor logistic regression analysis (odds ratio=2.42, 3.47, 7.52, 5.61, 95% confidence interval=1.99-2.95, 1.86-3.92, 2.87-9.68, 2.14-14.69,

<0.01). For 43 patients with burn delayed resuscitation, the AUC of receiver′s operating characteristic curve of serum AFR at 12 h after burn for predicting AKI was 0.739 (95% confidence interval=0.576-0.903), the optimal threshold was 9.90, the sensitivity was 82%, and the specificity was 90%. The AUC of urinary HSP70 at 12 h after burn was 0.990 (95% confidence interval=0.920-1.000), the optimal threshold was 1.40 μg/L, the sensitivity was 98%, and the specificity was 96%. The AUC of urinary TIMP-2×IGFBP-7 at 24 h after burn was 0.715 (95% confidence interval=0.512-0.890), the optimal threshold was 114.20 μg²/L², the sensitivity was 91%, and the specificity was 95%. The AUC of urinary NGAL at 24 h after burn was 0.972 (95% confidence interval=0.860-1.000), the optimal threshold was 78 μg/L, the sensitivity was 95%, and the specificity was 96%. Conclusions Urinary HSP70 and NGAL have higher value in early diagnosis of AKI in burn patients with delayed resuscitation.