Value of combined measurement of serum cystatin C and urinary neutrophil gelatinase-associated lipocalin in diagnosis of acute kidney injury secondary to cirrhotic ascites

Objective To investigate the value of combined measurement of serum cystatin C ( Cys C) and urinary neutrophil gelatinase-associated lipocalin ( NGAL) in the diagnosis of AKI secondary to cirrhotic ascites. Methods A total of 105 patients with cirrhotic ascites who were admitted to Sichuan Provincial People's Hospital from January 2015 to June 2016 were enrolled and divided into AKI group with 56 patients and non-AKI group with 49 patients. Meanwhile, 40 healthy persons who underwent physical examination were enrolled as controls. The indices including serum Cys C, urinary NGAL, serum creatinine ( Scr) , and glomerular filtration rate ( GFR) were observed. The 105 patients with cirrhotic ascites were divided into subgroups according to Child-Pugh class, and the changes in serum Cys C, urinary NGAL, Scr, and GFR were compared between these subgroups. The independent samples t-test was used for comparison of continuous data between two groups; a one-way analysis of variance was used for comparison between multiple groups, and the SNK-q test was used for further comparison between any two groups. The chi-square test was used for comparison of categorical data between groups, and a Pearson correlation analysis was also performed. Results There were significant differences in the levels of serum Cys C and urinary NGAL between the AKI group and the non-AKI group, as well as between the AKI group and the healthy control group ( all P < 0. 01) . AKI stage was determined for all AKI patients, and the AKI patients with a higher stage had significantly higher levels of serum Cys C and urinary NGAL than those with a lower stage ( all P < 0. 05) . Of all 56 AKI patients, 11 ( 19. 6% ) died; the patients who died had significantly higher levels of serum Cys C and urinary NGAL than those who survived ( t =-7. 742 and-3. 209, both P < 0. 01) . The correlation analysis showed that the levels of serum Cys C and urinary NGAL were negatively correlated with GFR ( r =-0. 915 and-0. 793, both P < 0. 01) . The levels of serum Cys C and urinary NGAL increased significantly and GFR decreased significantly with the increase in Child-Pugh class ( all P <0. 05) . Conclusion Combined measurement of serum Cys C and urinary NGAL can be used for the early diagnosis of AKI secondary to cirrhotic ascites and the evaluation of the severity and prognosis of AKI.