Importance and benefits of dietary sodium restriction in the management of chronic kidney disease patients: experience from a single Chinese center.

AIM

Several studies have suggested that sodium intake may affect blood pressure (BP), proteinuria, and intrarenal transforming growth factor-β1 (TGF-β1) production in patients and animal models with chronic kidney disease (CKD). The Chinese population has a high prevalence of CKD and is well known for consuming salty foods. This study will investigate the role of dietary sodium intake on BP control among non-dialysis Chinese CKD patients.

METHODS

A cross-sectional study was carried out in a cohort of 176 non-dialysis hypertensive CKD patients to investigate their sodium intake and its effect on BP control by measuring 24-h urine sodium excretion (24-h UNa). A total of 20 patients with immunoglobulin A nephropathy (IgAN) participated in a 7-day sodium restriction study (100 mmol/day). Their changes in BP, proteinuria, and urinary TGF-β1 excretion were subsequently analyzed. Another 23 IgAN patients without salt restriction were included as controls.

RESULTS

The average 24-h UNa of the study cohort was 149.0 ± 66.4 mmol/day. Only 31.8% patients had a 24-h UNa less than 100 mmol/day. The OR for each 17 mmol increment in 24-h UNa (salt 1 g/day) for BP > 130/80 mmHg was 1.26 (95% CI 1.10-1.44, P = 0.001). The sodium restriction group achieved significantly more reduction in SBP (-11.1 mmHg vs. -5.0 mmHg, P = 0.022), DBP (-9.4 mmHg vs. -2.1 mmHg, P = 0.009), and urine protein excretion [-465 (-855 to -340) mg/day vs. -150 (-570 to 40) mg/day, P = 0.024]. A positive correlation was observed between the change of 24-h UNa and the change of SBP (r = 0.450, P = 0.047) in the sodium restriction group. The change of 24-h UNa was also correlated with the 24-h TGF-β1 excretion (r = 0.558, P = 0.011) in these patients.

CONCLUSION

Dietary sodium intake restriction should be monitored and intensified in the treatment of Chinese CKD patients.