Sodium Bicarbonate Treatment and Vascular Function in CKD: A Randomized, Double-Blind, Placebo-Controlled Trial

Area of Science:

• Nephrology
• Cardiology
• Vascular Biology

Background:

• Lower serum bicarbonate levels are linked to cardiovascular disease (CVD) risk in chronic kidney disease (CKD).
• The role of normal serum bicarbonate levels and potential interventions like sodium bicarbonate (NaHCO 3 ) in CKD vascular function require further investigation.
• Prospective interventional trials are needed to clarify the effects of NaHCO 3 in CKD.

Purpose of the Study:

• To investigate the effect of sodium bicarbonate (NaHCO 3 ) supplementation on vascular function in patients with CKD stages 3b-4 and normal serum bicarbonate levels.
• To assess the impact of NaHCO 3 on arterial stiffness, flow-mediated dilation, and left ventricular mass index.
• To evaluate the safety and tolerability of NaHCO 3 therapy in this patient population.

Main Methods:

• A randomized, double-blind, placebo-controlled trial involving 109 patients with CKD stage 3b-4 (eGFR 15-44 ml/min/1.73 m 2).
• Participants received either NaHCO 3 or placebo (0.5 mEq/lean body weight-kg/day) for 12 months.
• Coprimary end points included changes in brachial artery flow-mediated dilation (FMD) and aortic pulse wave velocity (PWV).

Main Results:

• NaHCO 3 increased plasma bicarbonate levels, urinary citrate, and pH, while decreasing urinary ammonium, confirming intervention effectiveness.
• No significant improvements were observed in aortic pulse wave velocity or left ventricular mass index after 12 months.
• A transient increase in flow-mediated dilation was noted at 1 month but not sustained at 6 or 12 months.
• Treatment was safe, with no significant changes in blood pressure, weight, or edema.

Conclusions:

• Sodium bicarbonate (NaHCO 3 ) supplementation does not improve vascular endothelial function or reduce arterial stiffness in CKD patients with normal serum bicarbonate levels.
• The findings do not support the use of NaHCO 3 for treating vascular dysfunction in this specific CKD population.
• While safe, NaHCO 3 did not confer the anticipated cardiovascular benefits in the studied cohort.