Improvement of visit-to-visit SBP variability with lowering dialysate sodium concentration in patients undergoing hemodialysis: a randomized controlled trial

BACKGROUND: Hypertension is considered a significant modifiable risk factor for cardiovascular disease among hemodialysis patients. Aside from blood pressure (BP) levels, blood pressure variability (BPV) has been independently associated with all-cause and cardiovascular mortality in hemodialysis patients. Sodium load is associated with thirst, fluid retention, interdialytic weight gain (IDWG), and hypertension. This study investigated the effect of lowering dialysate sodium concentration on visit-to-visit BPV in hemodialysis patients. METHODS: Among 110 hemodialysis patients assessed for eligibility, 89 were randomized to receive hemodialysis either with standard dialysate sodium (143 mmol/l) or reduced dialysate sodium (140 mmol/l) for 3 months. Eighty-three patients completed the study. Predialysis BP readings were recorded with an automated device 2 weeks before and after the intervention. The visit-to-visit BPV was quantified at baseline and after 3 months by three metrics: the standard deviation (SD) of the BP, the coefficient of variation (CV), and the average real variability (ARV). RESULTS: SD ( P = 0.02), CV ( P = 0.034), and ARV ( P < 0.001) of SBP were significantly decreased in the lower sodium dialysate group. No significant difference was observed between both groups in terms of diastolic BPV measures. Furthermore, IDWG was significantly decreased in the lowered sodium dialysate group after 3 months ( P = 0.02). Intradialytic adverse events were comparable for both groups. CONCLUSION: Lowering dialysate sodium concentration decreases visit-to-visit systolic BPV parameters and IDWG. Long-term studies are required to confirm postulated cardiovascular benefits. TRIAL REGISTRATION: The trial was registered with ClinicalTrials.gov (trial registration number NCT05169125, trial registration date 23/12/2021).