Effect of Low-Sodium versus Conventional Sodium Dialysate on Left Ventricular Mass in Home and Self-Care Satellite Facility Hemodialysis Patients: A Randomized Clinical Trial
Authors: Marshall Mark R. , Vandal Alain C. , de Zoysa Janak R. , Gabriel Ruvin S. , Haloob Imad A. , Hood Christopher J. , Irvine John H. , Matheson Philip J. , McGregor David O.R. , Rabindranath Kannaiyan S. , Schollum John B.W. , Semple David J. , Xie Zhengxiu , Ma Tian Min , Sisk Rose , Dunlop Joanna L. 
Published: March 2020

Significance Statement
Because fluid overload in patients undergoing hemodialysis contributes to cardiovascular morbidity and mortality, there is a global trend to use low-sodium dialysate in hemodialysis with the goal of reducing fluid overload. To investigate whether lower dialysate sodium during hemodialysis improves left ventricular mass, the authors conducted a randomized clinical trial of 99 adults that compared use of low-sodium dialysate (135 mM) with conventional dialysate (140 mM) for 12 months. Although participants with lower dialysate sodium showed significant improvement in fluid status, the intervention had no effect on left ventricular mass index. The intervention also increased intradialytic hypotension. Given these findings, the current trend to lower dialysate sodium should be reassessed, pending the results of large trials with hard clinical end points.

Background
Fluid overload in patients undergoing hemodialysis contributes to cardiovascular morbidity and mortality. There is a global trend to lower dialysate sodium with the goal of reducing fluid overload.

Methods
To investigate whether lower dialysate sodium during hemodialysis reduces left ventricular mass, we conducted a randomized trial in which patients received either low-sodium dialysate (135 mM) or conventional dialysate (140 mM) for 12 months. We included participants who were aged >18 years old, had a predialysis serum sodium ≥135 mM, and were receiving hemodialysis at home or a self-care satellite facility. Exclusion criteria included hemodialysis frequency >3.5 times per week and use of sodium profiling or hemodiafiltration. The main outcome was left ventricular mass index by cardiac magnetic resonance imaging.

Results
The 99 participants had a median age of 51 years old; 67 were men, 31 had diabetes mellitus, and 59 had left ventricular hypertrophy. Over 12 months of follow-up, relative to control, a dialysate sodium concentration of 135 mmol/L did not change the left ventricular mass index, despite significant reductions at 6 and 12 months in interdialytic weight gain, in extracellular fluid volume, and in plasma B-type natriuretic peptide concentration (ratio of intervention to control). The intervention increased intradialytic hypotension (odds ratio [OR], 7.5; 95% confidence interval [95% CI], 1.1 to 49.8 at 6 months and OR, 3.6; 95% CI, 0.5 to 28.8 at 12 months). Five participants in the intervention arm could not complete the trial because of hypotension. We found no effect on health-related quality of life measures, perceived thirst or xerostomia, or dietary sodium intake.

Conclusions
Dialysate sodium of 135 mmol/L did not reduce left ventricular mass relative to control, despite improving fluid status.

Clinical Trial registry name and registration number:
The Australian New Zealand Clinical Trials Registry, ACTRN12611000975998.