Carotid intima media thickness is independently associated with urinary sodium excretion in patients with chronic kidney disease

Figures & data

Figure 1. Carotid artery intima-media thickness (in mm) of the normal sodium group (urinary sodium excretion <85 mmol/day) and the excessive sodium group (urinary sodium excretion ≥85 mmol/day). Note: Data are mean with 95% confidence interval.

Table 1. Demographic, clinical, and laboratory parameters of the patients.

	Sodium excretion (mmol/day)		Mean IMT (mm)
	<85	≥85	<0.750	≥0.750
n	44	149	88	105
Age years	47.7 ± 10.6	49.7 ± 11.0	45.1 ± 12.2	52.3 ± 8.3###
Gender F n (%)	29 (66)	80 (54)	55 (63)	54 (51)
Smoke n (%)	3 (6.8)	9 (6.0)	3 (3.4)	9 (8.6)
SBP (mmHg)	121 ± 17	130 ± 19*	124 ± 17	131 ± 20#
DBP (mmHg)	75 ± 10	80 ± 14*	77 ± 13	80 ± 14#
MAP (mmHg)	89 ± 11	100 ± 15*	93 ± 13	97 ± 15#
BMI (kg/m^2)	26.0 ± 3.43	27.1 ± 4.1	26.1 ± 4.2	27.6 ± 3.7#
IMT (mm)	0.726 ± 0.149	0.792 ± 0.182*	.627 ± 0.090	0.902 ± 0.128###
FBS (mg/dL)	88.3 ± 8.0	90.4 ± 9.4	89.1 ± 8.9	90.6 ± 9.4
Uric acid (mg/dL)	6.6 ± 1.7	6.9 ± 1.4	6.6 ± 1.3	6.9 ± 1.6
Triglycerides (mg/dL)	177 ± 142	162 ± 100	154 ± 107	174 ± 114
TC (mg/dL)	205 ± 58	195 ± 54	201 ± 62	194 ± 49
LDL (mg/dL)	122 ± 44	121 ± 45	124 ± 50	119 ± 39
HDL (mg/dL)	46.5 ± 11.1	45.6 ± 11.1	46.9 ± 11.1	44.9 ± 11.0
Sodium (mmol/L)	140 ± 3	140 ± 3	140 ± 2	140 ± 3
Calcium (mg/dL)	9.1 ± 0.5	9.1 ± 0.5	9.1 ± 0.5	9.1 ± 0.5
Phoshate (mg/dL)	3.7 ± 0.7	3.5 ± 0.9	3.5 ± 0.8	3.6 ± 0.9
iPTH (pg/mL)	130 ± 170	130 ± 87	125 ± 90	133 ± 126
Urea (mg/dL)	64 ± 23	79 ± 27	65 ± 25	72 ± 26#
Creatinine (mg/dL)	1.80 ± 0.8	2.13 ± 0.9*	1.97 ± 0.9	2.13 ± 0.8
GFR mL/min 1.73m^2	38.8 ± 15.5	34.9 ± 16.2	38.8 ± 17.2	33.2 ± 14.8#
UNaE (mmol/day)	63 ± 16	158 ± 58**	122 ± 60	148 ± 66#
UAE (mg/day)	642 ± 936	709 ± 945	629 ± 879	749 ± 990
UPE (g/day)	1.02 ± 1.43	1.24 ± 1.90	1.09 ± 1.43	1.28 ± 1.86
hs-CRP (mg/dL)	1.20 ± 1.19	1.37 ± 2.06	0.84 ± 0.84	1.74 ± 2.38##
Leucocytes × 10^3mL	7.07 ± 2.06	7.66 ± 2.03	7.29 ± 1.89	7.72 ± 2.19
Platelets X10^3 mL	225 ± 50	245 ± 73	240 ± 79	242 ± 70
Hemoglobin (g/dL)	12.5 ± 1.72	12.6 ± 1.63	12.4 ± 1.7	12.7 ± 1.6

Notes: SBP, systolic blood pressure; DBP, diastolic blood pressure; MBP, mean blood pressure; TC, total cholesterol, LDL, low-density lipoprotein cholesterol; HDL, high-density lipoprotein cholesterol; iPTH, intact parathormone; GFR, glomerular filtration rate; UNaE, urinary sodium excretion; UAE, urinary albumin excretion; UPE, urinary protein excretion; hs-CRP, high sensitive C-reactive protein.

*p < 0.05 and **p < 0.005 are the constraints in comparing between the patients with normal urinary sodium excretion and patients with high urinary sodium excretion; #p < 0.05, ##p < 0.005 and ###p < 0.0005 are the constraints in comparing between the patients with normal intima-media thickness and patients with elevated intima-media thickness.

Figure 2. Urinary sodium excretion (in mmol/day) of the group without subclinic atherosclerosis (intima-media thickness <0.750 mm) and the group with subclinic atherosclerosis (intima-media thickness ≥0.750 mm). Note: Data are mean with 95% confidence interval.

Figure 3. Relationship between carotid artery intima-media thickness and urinary sodium excretion. Scattergram, showing the relation between carotid artery intima-media thickness (in mm) and urinary sodium excretion (in mmol/day) in patient with chronic kidney disease.

Table 2. Univariate associations of covariates with carotid intima-media thickness.

	r	p
Age (years)	0.421	<0.001
High selective C-reactive protein (mg/dL)	0.266	<0.001
Urinary sodium excretion (mmol/day)	0.250	<0.001
Body mass index (kg/m^2)	0.221	0.002
Systolic blood pressure (mm Hg)	0.220	0.002
Mean arterial pressure (mm Hg)	0.190	0.008
Glomerular filtration rate (mL/min 1.73 m^2)	−0.190	0.008
Hemoglobin (g/dL)	0.156	0.030
Triglycerides (mg/dL)	0.146	0.043
Diastolic blood pressure (mm Hg)	0.141	0.049

Table 3. Multivariate linear regression analyses for carotid artery intima-media thickness in patients.

Factor	Increase in IMT (95% CI)	p
per 10 years increase in age	0.055 (0.035–0.074)	<0.001
per 1 mg/dL increase in hs-CRP	0.023 (0.012–0.034)	<0.001
per 2 g/day increase in urinary Na^+ excretion	0.031 (0.004–0.059)	0.025
per 1 g/dL increase in hemoglobin	0.025 (0.012–0.039)	0.001
per 10 mL/min 1.73 m^2 decrease in GFR	0.020 80.035–0.057)	0.007
per 10 mm Hg increase in systolic BP	0.012 (0.001–0.023)	0.038

Notes: Linear Regression Analysis, Method: Stepwise (Adjusted R²= 0.339; p < 0.000001).

Dependent Variable: Carotid artery intima-media thickness.

Independent Variables: Age, high selective C-reactive protein (hs-CRP), daily urinary sodium (Na⁺) excretion, systolic blood pressure (BP), glomerular filtration rate (GFR), hemoglobin, triglycerides.