The value of neutrophil gelatinase-associated lipocalin in early diagnosis of sepsis complicated by acute kidney injury

Yu Shan-shan; Liang Xian-quan; Yu Xue-zhong; Zhang Kai-kai

doi:10.3969/j.issn.1002-1949.2017.03.004

Abstract：Objective To investigate the value of nuetrophil gelatinase-associated lipocalin (NGAL) in early diagnosis of sepsis complicated by acute kidney injury (AKI),and to provide prognostic assessment of the patients with sepsis complicated by AKI.Methods We conducted a retrospective analysis of the clinical data of the sepsis patients who were admitted to the Guizhou Medical University Affiliated Hospital EICU and MICU,the ICU of Jinyang Hospital and ICU of Guizhou Cancer Hospital from March 2015 to February 2016,and then divided the patients according to their conditions into the sepsis group and the serious sepsis group.According to the diagnostic criteria of AKIN for diagnosing AKI,the author added up the cases of patients with complicated AKI from each group,meanwhile compares the levels of urinary NGAL,SCr and Cys-C of the patients from AKI group and non-AKI group upon the entry into the laboratory,2,6,12,24 and 48 hours after the entry into the laboratory respectively.We calculated the area under the curve (AUC) of receiver operator characteristic curve (ROC curve),and the optimal cutoff value of diagnosis of AKI with NGAL,and then calculated its sensitivity,specificity,positive likelihood ratio,negative likelihood ratio and Youden's index.We compared the score correlation of NGAL,Cys-C and APACHE Ⅱ from each viewpoint,and compared the related prognostic indicators of the patients from AKI group and non-AKI group.Results ①We drew the ROC curve according to the related data of urinary NGAL,SCr and Cys-C,and calculates the AUC.Consequently,the AUC of urinary NGAL was 0.970 (95％CI 0.921 ～ 0.991);the AUC of SCr was 0.788 (95％CI 0.682 ～ 0.894);and the AUC of Cys-C was 0.849 (95％CI 0.753 ～ 0.945).As to the AKI diagnosed by urinary NGAL,its sensitivity was 93.1％;its specificity was 88.6％.We chose the point that was close to the upper left of the ROC curve as possible as the optimal critical point.The corresponding concentration of urinary NGAL of this point was 11.42 ng/mL,which was the value of the optimal critical point of AKI diagnosed by urinary NGAL.②According to the comparison of the score correlation of NGAL,Cys-C and APACHE Ⅱ from each viewpoint of the patients,the related biological indicators of AKI diagnosis was positively correlated with the APACHE Ⅱ score.The urinary NGAL and APACHE Ⅱ score-related indicators reached the top two hours after the entry into the laboratory.The related indicators of correlation between the APACHE Ⅱ and the hemal Cys-C,and the correlation between the APACHE Ⅱ and the urinary NGAL was 0.573 and 0.859 respectively.This indicated that the AKI occurrence condition depends on the severity of the sepsis,which means the worse condition of the patient was,the higher the AKI occurrence rate would be.③According to the comparison of the related prognostic indicators of the patients from AKI group and non-AKI group,it indicated that as the length of stay and ICU residence time of the patients from the AKI group extended evidently,the survival rate of 28 d decreased.The differences were of statistical significance (P ＜ 0.05).It indicated that AKI evidently intervene the prognosis of the patients with sepsis.Enhancing the diagnosis and treatment of the AKI patients can evidently improve the prognosis of the patients with sepsis.Conclusion Compared with SCr and Cys-C,urinary NGAL can diagnose that the AKI happens to the patients with sepsis earlier.Its diagnostic value is higher than that of SCr or Cys-C.The occurrence of AKI depends on the severity of sepsis,and has influence on the prognosis of the patients with sepsis.As the length of stay and ICU residence time of the patients from the AKI group extends,the survival rate of 28 d decreases.