The value of cystatin C in predicting perioperative and long-term prognosis of renal transplantation

Figures & data

Table 1. The CKD-EPI formula for calculating eGFR.

Type	Gender	sCr (mg/dL)	Cys C (mg/L)	Formula
CKD-EPIsCr	female	≤0.7	–	144 × (sCr /0.7)^−0.329 × 0.993^age
	female	>0.7	–	144 × (sCr /0.7)^−1.209 × 0.993^age
	male	≤0.9	–	144 × (sCr /0.7)^−0.411 × 0.993^age
	male	>0.9	–	144 × (sCr /0.7)^−1.209 × 0.993^age
CKD-EPICys C	female	–	≤0.8	133 × (Cys C/0.8)^−0.499 × 0.996^age × 0.932
	female	–	>0.8	133 × (Cys C/0.8)^−1.328 × 0.996^age × 0.932
	male	–	≤0.8	133 × (Cys C/0.8)^−0.499 × 0.996^age
	male	–	>0.8	133 × (Cys C/0.8)^−0.499 × 0.996^age

CKD-EPI: Chronic kidney disease epidemiology cooperative group; Cys C: cystatin C; sCr: serum creatinine. 1 mg/dL = 17.1umol/L.

Table 2. Baseline clinical features of patients with or without DGF.

Variables	DGF group	Non-DGF group	p-value
Total	39	159	–
Age (years)	43.9 ± 8.6	41.2 ± 10.3	.61
Male, n (%)	23 (58.9%)	108 (67.9%)	–
BMI (kg/m^2)	19.8 ± 3.6	21.8 ± 4.1	.82
Cause of ESRD, n (%)
Glomerulonephritis	14 (35.9)	56 (35.2)	–
Diabetic nephropathy	7 (17.9)	32 (20.1)	–
Polycystic kidney	12 (30.8)	44 (27.7)	–
Others	6 (15.4)	27 (16.9)	–
sCr before RT, μmol/L	850.5 ± 214.6	808.7 ± 260.8	.58
Pre-transplant therapy, n (%)
Peritoneal dialysis	13 (33.3)	49 (30.8)	–
Hemodialysis	26 (66.7)	110 (69.2)	–
Dialysis time (month)	35.2 ± 22.6	38.8 ± 17.7	.84
HLA mismatch number	4.4 ± 0.5	4.5 ± 0.4	.68
CDC, %	2.5 ± 0.5	2.7 ± 0.4	.35
Cold ischemia time (hours)	7.4 ± 1.1	7.6 ± 0.9	.64

Data are presented as mean ± SD. BMI: body mass index; CDC: complement-dependent cytotoxicity; DGF: delayed graft function; ESRD: end-stage renal disease; HLA: human leukocyte antigen; non-DGF: prompt graft function.

Table 3. The levels of Cys C and sCr in patients with or without DGF.

Variables (days after operation)	DGF	Non-DGF	p-value
Cys C, mg/L
1^st day	5.23 ± 1.51	3.94 ± 1.57	.0027
2^nd day	4.92 ± 1.55	3.47 ± 1.31	.0006
3^rd day	4.89 ± 1.43	3.51 ± 1.45	.0048
4^th day	4.84 ± 1.78	3.52 ± 1.61	.0023
5^th day	5.16 ± 1.59	3.49 ± 1.59	.0083
6^th day	4.94 ± 1.24	3.23 ± 1.46	.0023
7^th day	5.07 ± 1.67	3.18 ± 1.56	.0032
Discharge	2.8 ± 1.2	1.9 ± 0.8	.012
sCr, μmol/L
1^st day	764.8 ± 147.1	537.5 ± 194.7	.0018
2^nd day	653.9 ± 238.5	421.8 ± 223.3	.0098
3^rd day	573.5 ± 205.2	324.6 ± 175.2	.001
4^th day	554.1 ± 213.9	277.1 ± 174.3	.0004
5^th day	479.1 ± 229.9	243.5 ± 169.8	.0047
6^th day	475.5 ± 194.8	227.9 ± 162.5	.0021
7^th day	498.1 ± 235.7	204 ± 140.5	.0012
Discharge	148.6 ± 56.2	103.8 ± 20.4	.0013

Data are presented as mean ± SD. Cys C: the protein cystatin C; DGF: delayed graft function; non-DGF: prompt graft function; s-Cr: serum creatinine.

Figure 1. The longitudinal changes of cystatin C (Cys C) (left panel) and serum creatinine (sCr) (right panel) in delayed graft function (DGF) and prompt graft function (non-DGF) patients. The Cys C and sCr levels of DGF patients were higher than those of the non-DGF group at all time points. The sCr concentrations in both groups declined rapidly after surgery, the decrease in Cys C levels in the DGF group was slower than that in patients without DGF.

Figure 2. ROC analysis of sCr (A) and Cys C (B) for predicting DGF. Both Cys C and sCr predicted DGF, Cys C showed the largest area under curve.

Table 4. The predictive value of Cys C and sCr by the ROC curves.

Biomarker	AUC, %	Cut-off value	Sensitivity, %	Specificity, %	p-value
Cys C
1^st day	92.8	4.9, mg/L	88.9	80	<.001
2^nd day	90	3.9, mg/L	86.2	75	.001
3^rd day	85.8	3.5, mg/L	85.8	65	.002
7^th day	81.4	3.1, mg/L	77.8	80	.008
sCr
1^st day	86.2	724.5, umol/L	85.5	75	.003
2^nd day	83.1	564.5, umol/L	86.2	70	.007
3^rd day	81.6	452.2, umol/L	85.2	70	.01
7^th day	78.1	399.1, umol/L	62.5	72	.02

Cys C: the protein cystatin C; sCr: serum creatinine; AUC: area under curve.

Table 5. SPS in RT recipients with or without DGF.

	DGF (n = 39）	Non-DGF (n = 159）	K	p-value
SPS	32	51	32.1	<.001
Non-SPS	7	108

SPS: shrunken pore syndrome; RT: renal transplantation; DGF: delayed graft function; non-DGF: prompt graft function;.

Table 6. The levels of Cys C and sCr in RT recipients with or without SPS.

	SPS (n = 83)	Non-SPS (n = 115)	p-value
BUN, mmol/L	5.7 ± 1.5	5.6 ± 1.8	.82
sCr, μmol/L	115.7 ± 33.5	124.8 ± 45.4	.27
Cys C, mg/L	2.2 ± 0.6	1.8 ± 0.7	<.001

Data are presented as mean ± SD. Cys C: the protein cystatin C; sCr: serum creatinine; RT: renal transplantation; SPS: shrunken pore syndrome; BUN: blood urea nitrogen.

Table 7. Follow-up of RT recipients with or without SPS.

	SPS	Non-SPS	p-value
BUN, mmol/L	7.6 ± 1.7	6.8 ± 1.9	.62
sCr, μmol/L	127.9 ± 22.5	97.8 ± 12.9	<.001
Cys C, mg/L	1.9 ± 0.3	1.2 ± 0.5	.01

Data are presented as mean ± SD. RT: renal transplantation; SPS: shrunken pore syndrome; BUN: blood urea nitrogen; Cys C: the protein cystatin C; sCr: serum creatinine.