Cystatin C is a biomarker for predicting acute kidney injury in patients with acute-on-chronic liver failure

Table 1 Clinical characteristics of the study population at admission

Parameter	ACLF (n = 56)	CHB (n = 30)	Control (n = 30)
Male/female	40/16	21/9	14/6
Age (yr)	44 ± 11	40 ± 10	39 ± 8
Alanine aminotransferase (IU/L)	145 ± 189	71 ± 61	21 (10-31)
Total bilirubin (mg/dL)	20.2 ± 5.6	2.2 ± 1.3	0.7 ± 0.2
Albumin (g/L)	30.4 ± 4.8	33.5 ± 5.2	35.6 ± 4.9
BUN (mmol/L)	4.4 ± 2.1	4.1 ± 1.8	4.8 ± 1.5
Plasma sodium (mEq/L)	134.8 ± 4.5	135.6 ± 5.7	137.4 ± 3.8
Cr (mg/dL)	0.9 ± 0.1	0.8 ± 0.1	0.8 ± 0.1
CysC (mg/L)	1.1 ± 0.4	0.7 ± 0.2	0.6 ± 0.3
International normalized ratio	1.9 ± 0.4	1.1 ± 0.2	0.9 ± 0.1
HBV DNA log10 (IU/mL)	4.75 ± 2.11	6.21 ± 2.78
Ishak score	ND	4 (3-5)1
MELD score	24 ± 3	8 ± 4

¹Histopathological data from 20 chronic hepatitis B (CHB) patients. ND: Not determined; BUN: Blood urea nitrogen; Cr: Creatinine; CysC: Serum cystatin C; HBV: Hepatitis B virus; MELD: Model for end-stage liver disease.

Table 2 Comparison of baseline clinical characteristics in patients with or without acute kidney injury during hospitalization

Parameter	Without AKI (n = 48)	With AKI (n = 8)	P (univariate)	P (multivariate)	OR (95%CI)
Age (yr)	41 ± 9	55 ± 7	< 0.001
Alanine aminotransferase (IU/L)	156 ± 158	62 ± 40	0.202
Albumin (g/L)	30.1 ± 5.1	30.2 ± 2.1	0.965
BUN (mmol/L)	4.2 ± 2.0	5.7 ± 1.1	0.065
Sodium (mEq/L)	135.3 ± 4.2	132.1 ± 3.8	0.064
Total bilirubin (mg/dL)	19.8 ± 5.6	21.3 ± 4.9	0.506
Cr (mg/dL)	0.9 ± 0.1	1.0 ± 0.2	0.792
International normalized ratio	1.9 ± 0.4	2.0 ± 0.3	0.367
MELD score	24 ± 3	26 ± 2	0.094
CysC (mg/L)	0.9 ± 0.3	1.8 ± 0.4	< 0.001	0.021	1.8 (1.4–2.3)

AKI: Acute kidney injury; BUN: Blood urea nitrogen; Cr: Creatinine; CysC: Serum cystatin C; MELD: Model for end-stage liver disease.

Table 3 Area under the curve for receiver operating characteristics and cutoff values for predicting acute kidney injury in acute-on-chronic liver failure patients

Parameter	Cutoff value	AUC (95%CI)	Sensitivity	Specificity	P value
CysC (mg/L)	1.21	0.974 (0.846-1.000)	100%	87.5%	< 0.0001
Cr (mg/dL)	1.1	0.526 (0.343-0.704)	37.5%	91.7%	0.828
BUN (mmol/L)	4.9	0.674 (0.487-0.829)	62.5%	79.2%	0.124
Serum sodium (mEq/L)	131	0.687 (0.500-0.839)	50%	87.5%	0.113

BUN: Blood urea nitrogen; Cr: Creatinine; CysC: Serum cystatin C; AUC: Area under the curve.