Effect of Different Dialysate Sodium Concentrations on Blood Pressure in Chronic Haemodialysis Patients: A Randomized Study.

Introduction: Hypertension is associated with higher cardiovascular morbidity and mortality in chronic haemodialysis patients. Altering dialysate sodium (dNa) concentration presents a possibility of sodium balance control and blood pressure (BP) management.

Methods: We performed a prospective, randomized, single-centre study, including 45 patients, divided into three groups of 15. Each group went through 3 periods of 2 months. The first group started with a dNa of 138 mmol/L in the first period, 140 mmol/L in the second, and 142 mmol/L in the third. The third group completed the study with the opposite dNa alteration (reduction from 142 to 138 mmol/L). The second group continued with 140 mmol/L throughout the study.

Results: In the first group, we found a statistically significant reduction of pre-dialysis systolic BP in the first period, compared with BP values before the study and a significant increase in pre-dialysis diastolic BP in the second period. Upon reduction of dNa from 140 to 138 mmol/L in the third group, the reduction of pre-dialysis systolic BP was approaching statistical significance. We did not find significant differences in BP values or the presence of hypotension between groups in each period. In the first group, we recorded a significant decrease in interdialytic weight gain and ultrafiltration volume in the first period and an increase in these parameters in the second. We were unable to reach a significant reduction in the latter after lowering dNa in the third group.

Conclusion: This study offers limited support for the idea that small reductions in fixed dNa (2 mmol/L) significantly change peri-dialytic BP values.