Management of Hyponatremia in CKD Stage 3b

Understanding the Clinical Context

• The Kidney Disease: Improving Global Outcomes (KDIGO) 2024 guidelines recommend sodium intake <2g/day (equivalent to <5g sodium chloride/day) for all CKD patients, as sodium restriction helps control hypertension, reduce proteinuria, and prevent volume overload 1, 2
• The Kidney Disease Outcomes Quality Initiative (KDOQI) 2020 guidelines recommend limiting sodium to <100 mmol/day (<2.3g sodium/day) to reduce blood pressure and improve volume control 3
• For patients with CKD, the current regimen of 1g sodium chloride daily provides approximately 393mg (17 mmol) of sodium, which is already well below the recommended upper limit, and mild hyponatremia requires investigation of the underlying cause rather than automatic sodium supplementation 1, 3

Critical Exception: Sodium-Wasting Nephropathy

• The only scenario where sodium supplementation would be appropriate is if the patient has sodium-wasting nephropathy, as explicitly stated in KDIGO 2024 Practice Point 3.3.2.1: "Dietary sodium restriction is usually not appropriate for patients with sodium-wasting nephropathy" 1, 2

Common Pitfall to Avoid

• The default approach in CKD is sodium restriction, not supplementation, and sodium supplementation is only appropriate in the specific circumstance of documented sodium-wasting nephropathy with clinical volume depletion 1, 2, 3