A randomized trial of sodium-restriction on kidney function, fluid volume and adipokines in CKD patients

• Published in: BMC nephrology Vol. 15; no. 1; p. 57
• Main Authors: Campbell, Katrina L, Johnson, David W, Bauer, Judith D, Hawley, Carmel M, Isbel, Nicole M, Stowasser, Michael, Whitehead, Jonathan P, Dimeski, Goce, McMahon, Emma
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 04.04.2014; BioMed Central
• Subjects: Adipokines - blood; Aged; Albumin; Body Fluids - metabolism; Creatinine - blood; Diet; Diet, Sodium-Restricted - methods; Double-Blind Method; Female; Glomerular Filtration Rate; Health aspects; Hospitals; Humans; Male; Medical research; Molecular weight; Mortality; Natriuretic Peptide, Brain - blood; Nephrology; Peptide Fragments - blood; Renal Insufficiency, Chronic - diagnosis; Renal Insufficiency, Chronic - diet therapy; Renal Insufficiency, Chronic - physiopathology; Reproducibility of Results; Rodents; Sensitivity and Specificity; Sodium; Studies; Treatment Outcome; Canada; Queensland Australia; Australia
• DOI: 10.1186/1471-2369-15-57
• ISSN: 1471-2369

Dietary sodium restriction is a key management strategy in chronic kidney disease (CKD). Recent evidence has demonstrated short-term reduction in blood pressure (BP) and proteinuria with sodium restriction, however the effect on other cardiovascular-related risk factors requires investigation in CKD. The LowSALT CKD study involved 20 hypertensive Stage III-IV CKD patients counselled by a dietitian to consume a low-sodium diet (<100 mmol/day). The study was a randomised crossover trial comparing 2 weeks of high-sodium (additional 120 mmol sodium tablets) and low-sodium intake (placebo). Measurements were taken after each crossover arm including BP (peripheral and central), adipokines (inflammation markers and adiponectin), volume markers (extracellular-to-intracellular [E/I] fluid ratio; N-terminal pro-brain natriuretic peptide [NT-proBNP]), kidney function (estimated Glomerular Filtration Rate [eGFR]) and proteinuria (urine protein-creatinine ratio [PCR] and albumin-creatinine ratio [ACR]). Outcomes were compared using paired t-test for each cross-over arm. BP-lowering benefits of a low-sodium intake (peripheral BP (mean ± SD) 148/82 ± 21/12 mmHg) from high-sodium (159/87 ± 15/10 mmHg) intake were reflected in central BP and a reduction in eGFR, PCR, ACR, NTproBNP and E/I ratio. There was no change in inflammatory markers, total or high molecular weight adiponectin. Short-term benefits of sodium restriction on BP were reflected in significant change in kidney function and fluid volume parameters. Larger, long-term adequately powered trials in CKD are necessary to confirm these results. Universal Trial Number U1111-1125-2149 registered on 13/10/2011; Australian New Zealand Clinical Trials Registry Number ACTRN12611001097932 registered on 21/10/2011.