Efficacy of Different Doses of Sodium in the Dialysis Fluid on the Levels of Calcium, Phosphorus and Parathyroid Hormone in Patients Undergoing Chronic Hemodialysis

Abstract

Background: For patients with end-stage renal disease (ESRD), chronic hemodialysis (HD) is a life-saving procedure. Currently, there is no consensus on the optimal sodium level in dialysis due to a lack of conclusive evidence on safety and efficacy. Objectives: Considering the importance of adjusting sodium levels in dialysis for HD patients, the present study aimed to investigate the effect of different sodium concentrations in dialysis fluid on calcium, phosphorus, and parathyroid hormone (PTH) levels in chronic HD patients. Methods: In this double-blind, randomized controlled clinical trial, 84 patients undergoing chronic HD at the dialysis centers of Golestan and Imam Khomeini Hospitals in Ahvaz, Iran, in 2023 were enrolled. One group of patients was treated with HD using a sodium concentration of 140 mmol/L, while another group was treated with a sodium concentration of 135 mmol/L. At the beginning of the study (before the start of HD), one month after the start of dialysis, and three months after the start of dialysis, the patients' serum calcium, phosphorus, and PTH levels were measured. The effects of low and normal sodium levels in the dialysis fluid on calcium, phosphorus, and PTH levels were then compared. Results: The mean age of the patients was 53.99 ± 14.61 years, with 64% being female (54 patients). The duration of dialysis was 7.95 ± 3.45 years. Calcium levels were not significantly different between the 135 mmol/L sodium group and the 140 mmol/L sodium group after 3 months of intervention (8.60 ± 0.92 vs. 8.36 ± 0.96, P = 0.94). Phosphorus levels in the 135 mmol/L sodium group and the 140 mmol/L sodium group were 5.77 ± 1.49 and 5.37 ± 1.28, respectively, with no remarkable difference after 3 months of intervention (P = 0.98). Parathyroid hormone levels differed between groups (P = 0.02), but there was no substantial disparity in efficacy between the two sodium dosages at varying time intervals (P = 0.28). Conclusions: Reducing the sodium concentration in dialysis had no effect on calcium and phosphorus levels. Although PTH levels differed between the two sodium dose groups, there was no substantial disparity in efficacy between the two sodium dosages at varying time intervals. Further multicenter studies with larger sample sizes are suggested to confirm these results.