Association between salt intake and long-term mortality in hemodialysis patients: A retrospective cohort study

Abstract

Background The association between salt intake and clinical outcomes in hemodialysis patients has been controversial. This study aimed to clarify the association between salt intake and mortality in hemodialysis patients. Method The present study included patients who underwent hemodialysis from June 1st 2016 to May 31st 2020. Corrected salt intake by ideal body weight was the main predictor of outcomes. Ideal body weight was calculated assuming that the ideal body mass index is 22 kg/m2 for the Japanese population. The multivariate Cox proportional hazards model was used to determine the association between corrected salt intake and mortality, adjusting for potential confounders. The outcomes considered were all-cause mortality and cumulative incidence of cardiovascular events at year 4. Result A total of 492 adult patients were enrolled in the study. The mean daily salt intake and corrected salt intake at baseline were 9.5 g/day and 0.17 g/kg/day, respectively. The low corrected salt intake group (< 0.13 g/kg/day) demonstrated the highest 4-year all-cause mortality. No association was observed between corrected salt intake and the cumulative incidence of cardiovascular events. In multivariate Cox proportional hazards analysis, only the group with corrected salt intake of 0.16–0.20 g/kg/day was associated with a decreased hazard risk for all-cause death compared with the low corrected salt intake group. Conclusion The present study found that a low salt intake was associated with high all-cause mortality in hemodialysis patients. Reduced long-term survival may be attributed to malnutrition resulting from excessive salt restriction.

Association between home meal preparers and salt intake in haemodialysis patients: a cross-sectional study

“…Nutritional guidance for haemodialysis patients in Japan is usually given to the patients regardless of who cooks in the home. While the salt intake standard for haemodialysis patients is less than 6 g/day, 14 the actual salt intake was 9.5 g in a previous study 32 and 9.96 g in our study, exceeding this standard. Although salt and fluid management based on an appropriate diet is vital to prevent the development of heart failure, the leading cause of death in haemodialysis patients, compliance with such management is low.…”

Tissue Sodium Accumulation Induces Organ Inflammation and Injury in Chronic Kidney Disease

“…The same study reported that patients with high average salt intake are more likely to be younger, male, overweight, and with more nutrient intake paralleling sodium intake [138]. Similar findings were also demonstrated in Japanese hemodialysis patients [139,140]. As sodium accumulation varies by individual, the ideal level of sodium intake in both normal populations and patients with renal failure remains controversial.…”

Results of Salt Intake Restriction Monitored with the New Sodium Control Biosensor

“…Unfortunately, it is known that efforts to intensify Na restriction may increase the risk of compromising energy intake [38]. A retrospective cohort study demonstrated that low-salt intake was related to high all-cause mortality in HD patients, possibly due to malnutrition in the context of excessive salt restriction [39]. Along the same line, another study reported that hyponatremia was associated with malnutrition, inflammation, and fluid overload [30], while a review of recommended dietary regimens in patients under HD showed that, since Na is used in a wide variety of foods, Na restriction could increase the risk of malnutrition and energy-protein loss.…”