Effect of Dialysate and Plasma Sodium on Mortality in a Global Historical Hemodialysis Cohort.
In a large multinational hemodialysis cohort, lower dialysate sodium concentrations (138 mmol/L or below) were independently associated with higher all-cause mortality compared with higher concentrations, challenging the assumption that lower dialysate sodium improves outcomes.
Background
Excess mortality in hemodialysis patients is largely cardiovascular and is linked to abnormal fluid status and plasma sodium. Lower dialysate sodium may increase sodium removal but at the cost of hypotonicity, reduced blood-volume refilling, and a higher risk of intradialytic hypotension, whereas higher dialysate sodium preserves hemodynamic stability but removes less sodium. The optimal prescribing standard has remained uncertain.
Study design
This retrospective cohort analyzed 68,196 incident hemodialysis patients from 875 Fresenius Medical Care clinics across 25 countries treated between 2010 and 2019, contributing over 2.1 million patient-months. Baseline dialysate sodium (138 mmol/L or below versus above 138 mmol/L) and plasma sodium categories defined exposure, and a multivariable Cox model stratified by country adjusted for demographic, treatment, and bioimpedance fluid-status variables.
Key findings
Dialysate sodium of 138 mmol/L was prescribed in 63.2 percent of patients. Over a median follow-up of 40 months, about one third of patients died. Dialysate sodium of 138 mmol/L or below was associated with higher mortality, with a multivariable hazard ratio of 1.57 (95 percent confidence interval 1.25 to 1.98) adjusted for plasma sodium. Subgroup analysis showed no evidence of effect modification by plasma sodium concentration.
Clinical implications
These observational findings question the prevailing practice of prescribing lower dialysate sodium and suggest higher concentrations may be associated with better survival. The authors and commentators caution that the association may be confounded by near-collinearity between dialysate sodium and country, and they stress that randomized trials are needed before changing standard dialysate sodium prescribing practices.
Category
Research
Source
J Am Soc Nephrol
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