Protein carbonyl: A sensitive marker reflecting oxidative stress in prevalent hemodialysis patients

Table 1 Comparison of socio-demographic and clinical data between the two groups, mean ± SD/n (%)

Item		ESRD group (n = 60)	Control group (n = 30)	P value
Age (years)		51.5 ± 13.5	53 ± 12	0.5941
BMI		29.32 ± 6.4	28.83 ± 6.8	0.7401
Sex	Male	34 (56.7)	18 (60)	0.7632
	Female	26 (43.3)	12 (40)
Smoking	Smoker	13 (21.7)	6 (20)	0.8552
	Non-smoker	47 (78.3)	24 (80)
Clinical data	SBP (mmHg)	140.4 ± 14.7	125.4 ± 9.8	< 0.0011
	DBP (mmHg)	85.3 ± 7.8	84.5 ± 6.6	0.674

¹Using independent t test.

²Using χ² test.

ESRD: End-stage renal disease; BMI: Body mass index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure.

Table 2 Clinical characteristics of included patients, mean ± SD/n (%)

Item		n = 60
Dialysis vintage (years)		5.7 ± 4.2
Access	A-V shunt	58 (95.6)
	Permcath	2 (4.4)
ESRD etiology	Analgesic nephropathy	5 (5.6)
	Diabetic nephropathy	11 (12.2)
	Glomerulonephritis	11 (12.2)
	Hypertensive nephropathy	19 (21.1)
	Obstructive uropathy	5 (5.6)
	Systemic lupus erythematosus	3 (3.3)
	Urinary tract infection	4 (4.4)
	Unknown	2 (2.2)
Comorbidities	Diabetes mellitus	14 (23.3)
	Hypertension	42 (70)
	Ischemic heart disease	14 (23.3)
	Cerebrovascular disease	1 (1.7)
	Heart failure	6 (6.7)
Interdialytic weight gain		2.58 ± 0.65
1		2 (3.3)
2		29 (48.3)
3		26 (28.9)
4		3 (3.3)
Medications used	Intravenous iron	24 (26.7)
	Ator	12 (13.3)
	Cinacalcet	8 (8.9)
	One-alpha	30 (33.3)

ESRD: End-stage renal disease.

Table 3 Comparison of laboratory data between the two groups, mean ± SD

Item	ESRD group (n = 60)	Control group (n = 30)	P value
Hemoglobin (gm/dL)	10.83 ± 1.4	11.51 ± 2.7	0.015a,1
Creatinine (mg/dL)	11.36 ± 2.8	1.3 ± 0.5	< 0.001a,1
ALB (gm/dL)	3.88 ± 0.5	4.42 ± 0.5	< 0.001a,1
Ca (mg/dL)	9.34 ± 4.6	10.76 ± 1.7	0.071
PO4 (mg/dL)	5.23 ± 2.1	3.97 ± 0.4	0.021a,1
Urea (pre) (mg/dL)	146.6 ± 32.4	-	-
Urea (post) (mg/dL)	55.7 ± 20.7	-	-
PTH (pg/mL)	449.7 ± 301.3	-	-
Ferritin (ng/mL)	389.3 ± 253.4	-	-
CRP (mg/dL)	16.8 ± 14.3	1 ± 2.3	< 0.001a,1
PCO (pmol/mg)	239.8 ± 107.7	72.2 ± 16.7	< 0.0012

^aP value < 0.05.

¹Using Mann-Whitney test.

²Using Independent t test.

ESRD: End-stage renal disease; ALB: Albumin; Ca: Calcium; PO₄: Phosphate; PTH: Parathyroid hormone; CRP: C-reactive protein; PCO: Protein carbonyl.

Table 4 Correlation between C-reactive protein and clinical and laboratory data in end-stage renal disease group

Item	CRP (mg/dL)		PCO (pmol/mg)
	r value	P value	r value	P value
Age (years)	0.292	0.023a	0.099	0.353
BMI	0.155	0.145	-0.014	0.899
SBP (mmHg)	-0.004	0.972	0.085	0.425
DBP (mmHg)	-0.078	0.468	0.144	0.175
Hemoglobin (gm/dL)	-0.120	0.261	-0.030	0.780
Creatinine (mg/dL)	-0.045	0.676	-0.085	0.428
ALB (gm/dL)	-0.061	0.569	-0.164	0.122
Ca (mg/dL)	0.205	0.052	-0.022	0.834
PO4 (mg/dL)	-0.028	0.795	-0.163	0.126
Urea (pre) (mg/dL)	0.033	0.757	0.186	0.079
Urea (post) (mg/dL)	0.113	0.289	0.213	0.103
PTH (pg/mL)	0.371	0.004a	-0.077	0.470
Ferritin (ng/mL)	-0.249	0.112	0.051	0.750

^aP value < 0.05.

r: Spearman correlation test; CRP: C-reactive protein; PCO: Protein carbonyl; BMI: Body mass index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; ALB: Albumin; Ca: Calcium; PO₄: Phosphate; PTH: Parathyroid hormone.

Table 5 Comparison of nutritional status between the two groups and between nutritional status and protein carbonyl in end-stage renal disease group, mean ± SD/n (%)

Item	Well	Mild	Moderate	Severe	P value
ESRD group	23 (38.3)	6 (10)	30 (50)	1 (1.7)	< 0.001a
Control group	14 (46.7)	13 (43.3)	3 (10)	0 (0)	-
PCO (pmol/mg)	245.8 ± 116.5	190 ± 57.1	249.8 ± 104.8	260	0.526

^aP value < 0.05.

ESRD: End-stage renal disease; PCO: Protein carbonyl.