The Effects of Proteinuria on Urinary Cystatin-C and Glomerular Filtration Rate Calculated by Serum Cystatin-C

Figures & data

Table 1.  Demographic characteristics and CKD stage of total patients.

	Subjects (N = 106)
Age (years)	56.74 ± 16.31
Sex (M/F)	58/47
DM/non-DM	55/50
NS/non-NS	38/67
BMI (kg/m^2)	23.75 ± 4.15
CKD stage
Stage 1	6 (5.7%)
Stage 2	6 (5.7%)
Stage 3	24 (22.9%)
Stage 4	26 (24.8%)
Stage 5	43 (41.0%)

Notes: DM, diabetes mellitus; NS, nephrotic syndrome; BMI, body mass index; CKD, chronic kidney disease.

Values reported are mean ± SD.

Table 2.  Laboratory data and Cys-C of total patients.

	Total patients (N = 105)
WBC (×1000)	7.92 ± 2.99
Hemoglobin (g/dL)	10.05 ± 2.07
Platelet (×1000)	260.43 ± 97.64
Total protein (g/dL)	6.20 ± 1.02
Albumin (g/dL)	3.31 ± 0.80
Total cholesterol (mg/dL)	198.69 ± 110.13
Triglyceride (mg/dL)	165.28 ± 87.14
BUN (mg/dL)	47.08 ± 20.00
Creatinine (mg/dL)	4.24 ± 3.28
Serum Cys-C (mg/dL)	2.91 ± 1.15
24-h urine protein (mg)	3118.75 ± 2956.05
Corrected 24-h urine protein (mg/L)	9477.37 ± 11,284.78
FE protein	11.66 ± 16.97
24-h urine albumin (mg)	2102.91 ± 2082.66
Corrected 24-h urine albumin (mg/L)	1940.30 ± 2364.23
FE albumin	4.25 ± 6.20
24-h urine Cys-C (mg/24 h)	1.68 ± 1.40
Corrected 24-h urine Cys-C (mg/L)	1.43 ± 1.43
FE Cys-C	0.37 ± 0.40
GFR-Cys-C (mL/min)	37.76 ± 20.36
GFR-MDRD (mL/min)	28.76 ± 28.04
GFR-Difference (mL/min)	−10.60 ± 14.55

Notes: BUN, blood urea nitrogen; FE, fractional excretion rate; Cys-C, cystatin-C; GFR, glomerular filtration rate; MDRD, modification of diet in renal disease; GFR-Difference, GFR-MDRD – GFR-Cys-C.

Values reported are mean ± SD.

Table 3.  Comparison of laboratory data and cys-C between NS (nephrotic proteinuria) and non-NS (subnephrotic proteinuria) groups.

	Non-NS	NS	p-Value
WBC (×1000)	8.16 ± 3.46	7.49 ± 1.89	ns
Hemoglobin (g/dL)	10.03 ± 2.13	10.09 ± 1.98	ns
Platelet (×1000)	263.03 ± 91.53	255.84 ± 108.72	ns
Total protein (g/dL)	6.54 ± 0.91	5.59 ± 0.91	0.000
Albumin (g/dL)	3.62 ± 0.65	2.76 ± 0.75	0.000
Total cholesterol (mg/dL)	175.21 ± 81.32	239.47 ± 139.49	0.012
Triglyceride (mg/dL)	149.46 ± 79.60	192.76 ± 93.74	0.014
BUN (mg/dL)	49.62 ± 26.70	42.60 ± 24.42	ns
Creatinine (mg/dL)	4.55 ± 3.52	3.68 ± 2.74	ns
Serum Cys-C (mg/dL)	3.08 ± 1.12	2.64 ± 1.16	ns
24-h urine protein (mg/24 h)	1362.22 ± 823.19	6279.26 ± 2697.32	0.000
Corrected 24-h urine protein (mg/L)	3380.25 ± 3509.07	20,353.33 ± 12,200.16	0.000
FE protein	4.74 ± 6.12	24.19 ± 22.48	0.000
24-h urine albumin (mg/24 h)	871.19 ± 619.90	4274.62 ± 1978.73	0.000
Corrected 24-h urine albumin (mg/L)	1029.55 ± 1303.71	3564.87 ± 2921.50	0.000
FE albumin	2.17 ± 3.21	8.00 ± 8.29	0.000
24-h urine Cys-C (mg/24 h)	1.57 ± 1.35	1.87 ± 1.50	ns
Corrected 24-h urine Cys-C (mg/L)	1.36 ± 1.31	1.56 ± 1.64	ns
FE Cys-C	0.37 ± 0.40	0.36 ± 0.40	ns
Age (years)	58.91 ± 16.14	52.92 ± 16.10	ns
BMI	23.21 ± 3.58	24.67 ± 4.91	ns
GFR-Cys-C (mL/min)	33.68 ± 14.29	44.17 ± 26.32	0.041
GFR-MDRD (mL/min)	25.75 ± 25.78	34.00 ± 31.21	ns
GFR-Difference (mL/min)	−10.84 ± 13.00	−10.23 ± 16.84	ns

Notes: BUN, blood urea nitrogen; BMI, body mass index; FE, fractional excretion rate; Cys-C, cystatin-C; GFR, glomerular filtration rate; MDRD, modification of diet in renal disease; GFR-Difference, GFR-MDRD – GFR-Cys-C; ns, nonsignificant; NS, nephrotic syndrome.

Values reported are mean ± SD.

Table 4.  Comparison of laboratory data and cys-C among CKD stages.

	Stage 1	Stage 2	Stage 3	Stage 4	Stage 5	p-Value
WBC (×1000)	7.09 ± 2.57	10.60 ± 7.78	7.37 ± 2.23	7.85 ± 2.53	8.01 ± 2.53	ns
Hemoglobin (g/dL)	11.26 ± 3.17	11.30 ± 2.01	10.77 ± 2.01	10.16 ± 2.06	9.24 ± 1.66	0.006
Platelet (×1000)	351.6 ± 102.4	280.5 ± 118.6	255.0 ± 92.5	257.3 ± 100.4	249.8 ± 92.8	ns
Total protein (g/dL)	5.71 ± 1.36	6.40 ± 1.05	6.03 ± 1.09	6.31 ± 1.17	6.26 ± 0.83	ns
Albumin (g/dL)	2.88 ± 1.24	3.28 ± 0.77	3.15 ± 0.92	3.39 ± 0.83	3.41 ± 0.65	ns
Total cholesterol (mg/dL)	369.6 ± 262.8	152.3 ± 44.9	201.4 ± 80.52	191.2 ± 88.6	183.9 ± 92.3	0.002
Triglyceride (mg/dL)	270.0 ± 115.6	122.3 ± 36.6	166.1 ± 88.4	166.0 ± 81.4	155.5 ± 82.8	0.028
BUN (mg/dL)	10.58 ± 4.43	16.96 ± 3.51	30.83 ± 13.74	48.15 ± 17.06	64.80 ± 24.51	0.000
Creatinine (mg/dL)	0.70 ± 0.16	1.00 ± 0.16	1.80 ± 0.47	3.28 ± 1.01	7.12 ± 3.18	0.000
Serum Cys-C (mg/dL)	0.93 ± 0.23	1.29 ± 0.27	2.29 ± 0.73	2.89 ± 0.92	3.72 ± 0.86	0.000
24-h urine protein (mg/24 h; ×1000)	5.46 ± 4.91	3.28 ± 3.75	3.63 ± 2.74	3.01 ± 3.56	2.54 ± 2.02	ns
Corrected 24-h urine protein (mg/L; ×1000)	1.84 ± 1.91	1.28 ± 1.65	1.21 ± 1.32	7.33 ± 8.52	9.83 ± 1.56	ns
FE protein	5.98 ± 6.62	5.94 ± 8.50	8.34 ± 14.27	9.95 ± 13.80	16.06 ± 20.87	ns
24-h urine albumin (mg/24 h; ×1000)	4.02 ± 3.65	2.27 ± 2.78	2.52 ± 1.96	2.02 ± 2.49	1.62 ± 1.23	ns
Corrected 24-h urine albumin (mg/L; ×1000)	2.71 ± 3.21	0.96 ± 1.10	2.42 ± 2.87	1.19 ± 1.28	9.35 ± 4.73	ns
FE albumin	1.89 ± 2.72	0.81 ± 1.08	2.03 ± 1.91	3.68 ± 6.80	6.58 ± 7.28	0.015
24-h urine Cys-C (mg/24 h; ×1000)	0.07 ± 0.03	0.54 ± 0.62	1.14 ± 1.38	1.95 ± 1.56	2.13 ± 1.17	0.001
Corrected 24-h urine Cys-C (mg/L)	0.04 ± 0.01	0.21 ± 0.21	0.77 ± 0.88	1.16 ± 1.12	11.65 ± 60.00	ns
FE Cys-C	0.005 ± 0.001	0.051 ± 0.053	0.088 ± 0.094	0.359 ± 0.331	0.629 ± 0.432	0.000
Age (year)	44.83 ± 20.46	55.50 ± 8.80	53.88 ± 16.49	60.65 ± 15.15	57.81 ± 16.68	ns
GFR-Cys-C (mL/min)	93.22 ± 20.13	65.96 ± 12.23	42.83 ± 15.45	34.72 ± 13.52	26.19 ± 6.14	0.000
GFR-MDRD (mL/min)	111.83 ± 14.95	64.03 ± 22.16	40.62 ± 9.98	20.89 ± 7.20	8.45 ± 3.46	0.000
GFR-Difference (mL/min)	15.38 ± 12.28	6.36 ± 8.41	−2.21 ± 14.29	−16.14 ± 13.96	−17.79 ± 5.18	0.000

Notes: BUN, blood urea nitrogen; FE, fractional excretion rate; Cys-C, cystatin-C; GFR, glomerular filtration rate; MDRD, modification of diet in renal disease; GFR-Difference, GFR-MDRD – GFR-Cys-C; ns, nonsignificant; CKD, chronic kidney disease.

Values reported are mean ± SD.

Table 5.  Comparison of laboratory data and cys-C between DM and non-DM groups.

	Non-DM	DM	p-Value
WBC (×1000)	8.24 ± 3.53	7.62 ± 2.40	ns
Hemoglobin (g/dL)	10.23 ± 2.11	9.89 ± 2.03	ns
Platelet (×1000)	252.48 ± 112.39	267.65 ± 82.40	ns
Total protein (g/dL)	6.09 ± 1.04	6.29 ± 1.00	ns
Albumin (g/dL)	3.22 ± 0.83	3.39 ± 0.77	ns
Total cholesterol (mg/dL)	208.08 ± 143.82	190.32 ± 67.82	ns
Triglyceride (mg/dL)	149.61 ± 87.91	179.25 ± 84.81	ns
BUN (mg/dL)	48.23 ± 29.44	46.03 ± 22.65	ns
Creatinine (mg/dL)	4.66 ± 3.86	3.85 ± 2.62	ns
Serum Cys-C (mg/dL)	2.83 ± 1.16	2.98 ± 1.15	ns
24-h urine protein (mg/24 h)	3083.56 ± 3298.07	3150.74 ± 2637.59	ns
Corrected 24-h urine protein (mg/L)	8665.10 ± 10,988.50	10,214.44 ± 11,600.08	ns
FE protein	9.94 ± 15.01	13.26 ± 18.61	ns
24-h urine albumin (mg/24 h)	2134.37 ± 2375.22	2074.31 ± 1797.94	ns
Corrected 24-h urine albumin (mg/L)	2397.89 ± 3013.58	1525.07 ± 1470.79	ns
FE albumin	4.71 ± 7.21	3.82 ± 5.13	ns
24-h urine Cys-C (mg/24 h)	1.31 ± 1.22	2.02 ± 1.48	ns
Corrected 24-h urine Cys-C (mg/L)	1.39 ± 1.53	1.47 ± 1.35	ns
FE Cys-C	0.29 ± 0.35	0.44 ± 0.43	ns
Age (years)	52.88 ± 17.72	60.25 ± 14.18	0.020
BMI	23.41 ± 3.78	24.05 ± 4.47	ns
GFR-Cys-C (mL/min)	37.68 ± 18.77	37.82 ± 21.89	ns
GFR-MDRD (mL/min)	27.73 ± 27.67	29.95 ± 28.60	ns
GFR-Difference (mL/min)	−12.25 ± 12.60	−9.14 ± 16.09	ns

Notes: BUN, blood urea nitrogen; BMI, body mass index; FE, fractional excretion rate; Cys-C, cystatin-C; GFR, glomerular filtration rate; MDRD, modification of diet in renal disease; GFR-Difference, GFR-MDRD – GFR-Cys-C; ns, nonsignificant.

Values reported are mean ± SD.

Table 6.  Comparison of laboratory data and cys-C between HTN and non-HTN groups.

	Non-HTN	HTN	p-Value
WBC (×1000)	7.72 ± 2.27	7.95 ± 3.19	ns
Hemoglobin (g/dL)	10.63 ± 1.70	9.95 ± 2.12	ns
Platelet (×1000)	226.74 ± 105.41	266.48 ± 95.57	ns
Total protein (g/dL)	6.20 ± 1.31	6.19 ± 0.97	ns
Albumin (g/dL)	2.92 ± 1.07	3.38 ± 0.73	0.035
Total cholesterol (mg/dL)	217.81 ± 195.50	195.21 ± 87.70	ns
Triglyceride (mg/dL)	169.81 ± 114.30	164.46 ± 82.06	ns
BUN (mg/dL)	42.15 ± 31.11	47.97 ± 25.07	ns
Creatinine (mg/dL)	3.20 ± 2.83	4.42 ± 3.33	ns
Serum Cys-C (mg/dL)	2.27 ± 1.09	3.05 ± 1.12	0.016
24-h urine protein (mg/24 h)	4528.51 ± 4024.70	2865.31 ± 2672.01	ns
Corrected 24-h urine protein (mg/L)	16,275.45 ± 18,167.74	8227.15 ± 9126.31	ns
FE protein	14.06 ± 21.85	11.22 ± 16.05	ns
24-h urine albumin (mg/24 h)	2947.30 ± 2895.49	1951.11 ± 1882.58	ns
Corrected 24-h urine albumin (mg/L)	2419.21 ± 3089.33	1852.22 ± 2216.84	ns
FE albumin	4.27 ± 8.35	4.24 ± 5.79	ns
24-h urine Cys-C (mg/24 h)	1.14 ± 1.38	1.79 ± 1.39	ns
Corrected 24-h urine Cys-C (mg/L)	0.81 ± 1.42	1.56 ± 1.41	ns
FE Cys-C	0.23 ± 0.48	0.40 ± 0.38	ns
Age (years)	54.38 ± 21.38	57.17 ± 15.34	ns
BMI	25.02 ± 4.15	23.51 ± 4.14	ns
GFR-Cys-C (mL/min)	50.90 ± 30.67	34.94 ± 16.37	ns
GFR-MDRD (mL/min)	45.87 ± 39.38	25.65 ± 24.45	ns
GFR-Difference (mL/min)	−2.57 ± 14.31	−12.37 ± 14.10	0.017

Notes: BUN, blood urea nitrogen; HTN, hypertension; BMI, body mass index; FE, fractional excretion rate; Cys-C, cystatin-C; GFR, glomerular filtration rate; MDRD, modification of diet in renal disease; GFR-Difference, GFR-MDRD – GFR-Cys-C; ns, nonsignificant.

Values reported are mean ± SD.

Figure 1.  Fractional excretion of Cys-C and 24-h urine Cys-C according to fractional excretion of albumin and GFR-MDRD in total patients.

Figure 2.  Serum Cys-C and GFR of Cys-C according to corrected urine Cys-C.

Figure 3.  GFR of Cys-C according to fractional excretion of albumin and 24-h urine Cys-C.

Figure 4.  Differences in GFR between Cys-C and MDRD according to fractional excretion of albumin, 24-h urine albumin, and body mass index.

Figure 5.  GFR of Cys-C and MDRD according to fractional excretion of albumin and 24-h urine albumin.