Table 3.

Antioxidative status in the study groups.

	CKD 1	CKD 2	CKD 3	CKD 4	HD	PD	P
SOD (U/mL)	81.89 ± 8.38	68.37 ± 2.45	60.23 ± 6.15	54.29 ± 2.94	49.01 ± 3.03	52.53 ± 4.33	<0.001
CAT (U/mL)	62.75 ± 5.42	57.76 ± 7.25	53.52 ± 8.48	51.22 ± 3.66	47.99 ± 5.90	51.92 ± 5.90	<0.001
GSH-Px (U/mL)	7.71 ± 1.01	6.62 ± 0.50	5.23 ± 0.71	5.01 ± 0.82	3.99 ± 1.39	4.94 ± 1.12	<0.001
GSH-GR (U/mL)	1.72 ± 0.06	1.45 ± 0.11	1.34 ± 0.12	1.07 ± 0.19	0.98 ± 0.19	1.13 ± 0.21	<0.001
Vit E (ng/mL)	0.81 ± 0.06	0.62 ± 0.04	0.43 ± 0.05	0.36 ± 0.01	0.29 ± 0.03	0.36 ± 0.01	<0.001
Fe (μg/dL)	81.44 ± 20.45	74.90 ± 8.53	67.00 ± 10.98	61.42 ± 22.08	59.22 ± 16.39	60.90 ± 19.72	<0.001
Bilirubin (mg/L)	6.37 ± 1.80	5.95 ± 1.96	5.50 ± 1.43	5.00 ± 1.41	4.48 ± 1.68	4.40 ± 1.07	<0.001

SOD: superoxide dismutase; CAT: catalase; GSH-Px: glutathione peroxidase; GSH-GR: glutathione reductase; Vit E: vitamin E; Fe: iron. Data are presented as the mean ± SD. Statistically significant differences between all the groups (P < 0.001).