Impact of Sodium Bicarbonate Supplementation on Kidney Function and Acid-Base Balance in Chronic Kidney Disease Patients: A Systematic Review.

Chronic kidney disease (CKD) is a global health burden, with metabolic acidosis being a common complication that accelerates disease progression and contributes to muscle wasting, bone demineralization, and systemic inflammation. Sodium bicarbonate (SB) supplementation is widely used to correct acidosis, but its effects on kidney function and clinical outcomes remain inconsistent. This systematic review evaluates the impact of SB on kidney function, acid-base balance, and secondary outcomes in patients with CKD. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic search of PubMed, Scopus, MEDLINE, and the Cochrane Library up to May 2025. Nine randomized controlled trials (RCTs) involving 1,354 patients were included. Studies assessed the effects of SB on estimated glomerular filtration rate (eGFR), serum bicarbonate, muscle mass, blood pressure, and adverse events. Risk of bias was evaluated using the Cochrane Risk of Bias 2 (RoB 2) tool. SB supplementation consistently improved serum bicarbonate levels across all included studies, with statistically significant increases reported. The impact on kidney function, however, was variable, with some trials demonstrating improved eGFR while others showed no significant benefit. Positive effects on muscle mass preservation were observed in several studies, though physical function and blood pressure outcomes remained inconsistent. The intervention was generally well-tolerated, though gastrointestinal-related adverse events were more frequent with bicarbonate therapy compared to controls. Methodological quality was strong overall, with most studies demonstrating low risk of bias. SB effectively corrects metabolic acidosis in CKD but demonstrates variable effects on kidney function and secondary outcomes. Benefits appear most pronounced in early-to-moderate CKD, while patients with advanced disease may derive limited renal protection. Clinicians should individualize therapy, balancing biochemical correction with tolerability and cost. Future research should prioritize long-term trials with standardized outcomes to clarify the role of SB in CKD management.