What question did this study set out to answer?

This study aims to evaluate the effects of sodium bicarbonate on indicators of volume retention in kidney transplant recipients with metabolic acidosis.

April 17, 2026Open Access

Effect of Sodium Bicarbonate on Indicators of Volume Retention in Metabolic Acidosis After Kidney Transplantation: A Post-Hoc Analysis.

Key Points

This study aims to evaluate the effects of sodium bicarbonate on indicators of volume retention in kidney transplant recipients with metabolic acidosis.
Post-hoc analysis of a randomized, placebo-controlled trial
Participants: 240 kidney transplant recipients
Intervention: Administered 1.5-4.5 g/day sodium bicarbonate or placebo for 24 months
Outcomes assessed included body weight, plasma aldosterone, and sodium balance
Statistical analysis using descriptive statistics and mixed-effects regression models
Weak evidence for changes in body weight and plasma renin levels between groups
Significant reduction in plasma aldosterone levels in the sodium bicarbonate group
Increased serum sodium and higher 24-hour sodium excretion in the sodium bicarbonate group
No major differences in antihypertensive usage between groups
No clear evidence of harmful volume retention effects from sodium bicarbonate

Abstract

Rationale P = 0.09), no evidence for N-terminal prohormone of brain natriuretic peptide (BGD: -0.03, 95% CI: -0.21 to 0.16; P = 0.78), plasma renin (BGD: -0.12, 95% CI: -0.34 to 0.09; P = 0.26), and aldosterone-to-renin ratio (BGD: -0.05, 95% CI: -0.28 to 0.18; P = 0.69), whereas there was substantial evidence for a treatment effect on plasma aldosterone (BGD: -0.17, 95% CI: -0.3 to -0.05; P = 0.007), the latter 4 log-transformed. There was weak evidence for an increased chance of nocturnal systolic blood pressure dipping (OR: 2.28; 95% CI: 0.88 to 5.87; P = 0.09). The use of antihypertensives and diuretics remained similar in both groups. Weak evidence for higher serum sodium (BGD: 0.51 mEq/L, 95% CI: 0.08 to 0.94; P = 0.02) and strong evidence for higher log-transformed 24 hour-sodium excretion (BGD: 0.16, 95% CI: 0.07 to 0.26; P ≤ 0.001) in the sodium bicarbonate group were identified. There was no or weak evidence for treatment effects on other secondary outcomes. Subgroup analyses showed no major differential effects.Limitations Post-hoc analysis, mainly Caucasian study population.Conclusions Our findings did not provide clear evidence for unfavorable effects of sodium bicarbonate on volume retention. Further research is required to clarify risks.Trial Registration ClinicalTrials.gov (ID: NCT03102996).Many kidney transplant recipients develop metabolic acidosis because the transplanted kidney may not fully restore acid–base balance. Sodium bicarbonate is commonly used to correct this, but its associated sodium load raises concerns about fluid retention. This study compared long-term sodium bicarbonate use with placebo and evaluated signs of volume overload, including changes in body weight, blood markers linked to fluid regulation, blood pressure patterns, and the use of blood pressure medications. Moreover, hospitalizations related to uncontrolled blood pressure or fluid overload were studied. Overall, the results showed no clear evidence of harmful effects. Further research should confirm these findings.

Effect of Sodium Bicarbonate on Indicators of Volume Retention in Metabolic Acidosis After Kidney Transplantation: A Post-Hoc Analysis.

Key Points

Abstract

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