Sodium Intake and Chronic Kidney Disease.

Area of Science:

• Nephrology
• Cardiology
• Dietary Science

Background:

• Elevated blood pressure (hypertension) is common in Chronic Kidney Disease (CKD), often linked to sodium and fluid retention.
• While salt restriction shows benefits in non-dialysis CKD, long-term effects on cardio-renal outcomes are debated due to potential biases and adherence issues.
• In end-stage kidney disease (ESKD), managing sodium intake is crucial as dialysis cannot fully compensate for dietary excess, leading to fluid overload and worsening prognosis.

Purpose of the Study:

• To evaluate the role of low salt diet (LSD) in managing hypertension and fluid overload in patients with Chronic Kidney Disease (CKD).
• To discuss the rationale and implementation of LSD across different stages of CKD, including end-stage kidney disease (ESKD).

Main Methods:

• Review of existing studies on salt restriction and its impact on blood pressure, proteinuria, and cardio-renal outcomes in CKD patients.
• Analysis of the physiological mechanisms linking sodium balance, fluid status, and hypertension in CKD.
• Discussion on the challenges and considerations for implementing LSD, including personalization and monitoring.

Main Results:

• Salt restriction can reduce blood pressure and enhance the efficacy of renin-angiotensin-aldosterone system inhibitors in non-dialysis CKD.
• Controversial findings exist regarding the long-term cardio-renal benefits of LSD, potentially due to measurement biases, reverse epidemiology, and poor adherence.
• In ESKD, LSD is essential to mitigate fluid overload and hypertension caused by the mismatch between sodium intake and removal during dialysis.

Conclusions:

• Low salt diet is a rational and fundamental strategy for managing fluid overload and hypertension in all stages of CKD.
• Personalized implementation of LSD, considering volume status and ambulatory blood pressure monitoring, is recommended, similar to diuretic therapy.