To assess the value of serum CysC combined with urinary NGAL in the diagnosis of acute kidney injury in patients with liver cirrhosis.

The clinical data of 120 cases of liver cirrhosis complicated with acute renal injury treated at the First People's Hospital of Tianmen, Hubei, China from April 2014 to April 2017 were retrospectively analyzed. According to the AKI criteria, the patients were divided into an AKI 1 group, AKI 2 group, and AKI 3 group, with 40 cases in each group. Forty cases who received normal health examination at the same hospital during the same period were selected as a control group. Urine NGAL was detected by solid phase sandwich enzyme-linked immunosorbent assay (ELISA), serum CysC was detected by ELISA, and creatinine (SCr) was detected by serum oxidase method. One-way analysis of variance was used to compare the difference of urine NGAL and serum CysC expression among the four groups, and the correlation between serum CysC, the level of urine NGAL, and the APACHE Ⅱ score was assessed by Pearson correlation analysis.

Serum CysC, urinary NGAL and Scr levels, and APACHEⅡ score increased with disease severity. Serum CysC levels in the three AKI groups were significantly different from that in the control group (q=4.807, P=0.036; q=15.449, P<0.001; q=23.942, P<0.001); a significant difference was also observed between the AKI 2/3 groups and AKI 1 group (q=10.641, P<0.001; q=19.136, P<0.001), as well as between the AKI 3 and AKI 2 groups (q=8.495, P=0.01). Urinary NGAL levels in the three AKI groups were significantly different from that in the control group (q=6.109, P=0.012; q=10.997, P<0.001; q=19.375, P<0.001); a significant difference was also observed between the AKI 2/3 groups and AKI 1 group (q=4.887, P=0.031; q=13.266, P<0.001), as well as between the AKI 3 and AKI 2 groups (q=8.378, P=0.004). Scr levels in the three AKI groups were significantly different from that in the control group (q=8.461, P=0.003; q=21.198, P<0.001; q=42.995, P<0.001); a significant difference was also observed between the AKI 2/3 groups and AKI 1 group (q=12.737, P<0.001; q=34.534, P<0.001), as well as between the AKI 3 group and AKI 2 group (q=21.797, P<0.001). APACHE Ⅱ score differed significantly between the AKI 2/3 groups and AKI 1 group (q=10.907, P<0.001; q=21.643, P<0.001), as well as between the AKI 3 group and AKI 2 group (q=10.737, P<0.001). The mortality rates differed significantly between the AKI 2/3 groups and the AKI 1 group (χ²=4.766, P=0.029, χ²=13.272, P<0.001), as well as between the AKI 2 and AKI 3 groups (χ²=5.208, P=0.022). APACHEⅡ score increased with the aggravation of the disease. APACHE Ⅱ score in the high CysC + high NGAL group was significantly higher than that in the high CysC alone group or high NGAL alone group (q=17.440, P<0.001; q=16.206, P<0.001). APACHE Ⅱ score was not significantly different between the high CysC alone group and high NGAL alone group (q=1.234, P=0.452). The mortality rate of patients with high CysC and high NGAL was significantly higher than that of patients with high CysC alone (χ²=8.010, P=0.005) or high NGAL alone (χ²=5.148, P=0.023). The mortality rate was statistically higher in the high CysC alone group than in the high NGAL alone group (χ²=1.173, P=0.279). Serum CysC and urinary NGAL in the death group were significantly higher than those in the survival group. APACHE score in the death group was signficantly higher than that of the survival group (t=18.872, P<0.001). Serum CysC and urinary NGAL levels were linearly correlated with APACHE score (r=0.868, P=0.003; r=0.721, P=0.008).

Urinary NGAL and serum CysC are the early indicators for predicting the onset of AKI, and combined detection of them can further improve the early diagnosis of AKI. Urinary NGAL and serum CysC can be used as indicators for evaluating the clinical condition and prognosis of liver cirrhosis patients with AKI.