Dietary and Dialysate Sodium Reduction on Body Fluid Volume and Inflammatory State in Hemodialysis Patients

Overview

Objective: To evaluate the influence of dietary sodium reduction on body fluid volume and inflammatory state in hemodialysis (HD) patients. Design: Prospective controlled randomized study. Setting: Dialysis Unit of Botucatu Medical School Hospital, Sao Paulo State University, Brazil. Patients: Adult patients on HD for at least 30 days and C-reactive protein (CRP) ≥ 0.7 mg/dl were randomly allocated into two groups: Group A: 21 patients treated with a 2g sodium restriction in their habitual diet, and Group B: 18 controls. Inflammatory, biochemical, hematological and nutritional markers, as well as dialysis dosage were assessed at baseline and after 8 and 16 weeks.

The prognosis of chronic kidney diseases (CKD) patients is strongly compromised by cardiovascular (CV) complications. Inflammation is established as a major risk factor for CV complications in these patients, occurring in approximately one third of them. Recently, growing evidences have suggested the body water volume expansion is a cause of inflammation in CKD. In a previous study Rodrigues Telini showed that dietary sodium restriction reduced the inflammatory markers levels in hemodialysis (HD) patients. Similar results were observed in patients treated by reduction of HD dialysate sodium concentration. However in both studies no significant reduction in body volume markers was observed. These results could be due to small number of patients or low sensibility of volume markers; on the other hand they could suggest a direct role of sodium as an inflammatory inducer independently of volume. With a larger number of patients and using a more sensitive volume marker as the B-type natriuretic peptide (BNP), this study intends to confirm the hypothesis that sodium mobilization can reduce the body water volume and attenuate the inflammatory in HD patients. A hundred thirty-five patients will be enrolled and divided in three groups with 35 patients: A, treated by reduction of 2 grams in daily sodium intake; B, exposed to reduction of sodium dialysate from 138 to 135 mEq/L and C, control group. The patients will be followed up by 16 weeks and inflammatory markers (CRP, interleukin-6, and tumor necrosis factor) as well as volume markers (Watson formula, electrical bioimpedance measurements and BNP concentration) will be determine each 8 weeks.