Clinical consequences of an individualized dialysate sodium prescription in hemodialysis patients

Background. Predialysis plasma sodium (Na+) concentration is relatively constant in hemodialysis (HD) patients, and a higher dialysate Na+ concentration can promote an increase in the interdialytic fluid ingestion to achieve an individual's osmolar set point, and individualization of dialysate Na+ concentration may improve interdialytic weight gain (IDWG), blood pressure (BP), and HD-related symptoms. Methods. Twenty-seven nondiabetic, non-hypotension prone HD patients were enrolled in a single-blind crossover study. Subjects underwent nine consecutive HD sessions with the dialysate Na+ concentration set to 138 mEq/L (standard Na+ HD), followed by nine sessions wherein the dialysate Na+ was set to match the patients average pre-HD plasma Na+ measured three times during the standard Na+ phase multiplied by 0.95 (individualized dialysate Na+ HD). Dry weight, dialysis prescription, and medications were not modified during the six weeks of the study. Results. Pre-HD Na+ was similar in both periods of the study (standard Na+ HD, 134.0 +/- 1.4 mEq/L; individualized Na+ HD, 134.0 +/- 1.5 mEq/L; P= 0.735). There was a significant decrease in interdialytic weight gain (2.91 +/- 0.87 kg vs. 2.29 +/- 0.65 kg; P< 0.001), interdialytic thirst scores, and episodes of intradialytic hypotension in the individualized Na+ period compared with the standard phase. Pre-HD BP was lower in individualized Na+ HD in patients with uncontrolled BP at baseline (N= 15), but not in those with controlled BP at baseline (N= 12) (DeltaBP -15.6/-6.5 mm Hg in uncontrolled vs. DeltaBP +6.4/+4.5 mm Hg in controlled, P= <0.001 for systolic BP and P= <0.001 for diastolic BP). Conclusion. An individualized Na+ dialysate based on predialysis plasma Na+ levels decreases thirst, IDWG, HD-related symptoms, and pre-HD BP (in patients with uncontrolled BP at baseline).