Metabolic acidosis is a common complication in chronic kidney disease (CKD) patients, and is associated with an accelerated decline in renal function. Oral bicarbonate therapy has been used to counteract metabolic acidosis in CKD for decades. However, until recently, there have been very few intervention studies testing the effectiveness of bicarbonate therapy at improving metabolic acidosis or its consequences in patients with CKD. In this systematic review and meta-analysis, we aimed to examine the outcomes of all published randomised controlled trials (RCTs) that investigated the effect of oral bicarbonate therapy in adults with CKD. Ovid MEDLINE®, EMBASE® and Cochrane Library were searched in mid-October 2018 for English literature, with no restrictions applied to the publication status or date. Seven RCTs that recruited 815 participants met our inclusion criteria after full text review. Oral bicarbonate supplementation resulted in a slightly higher estimated glomerular filtration rate (eGFR) (mean difference 3.1 mL/min per 1.73 m2; 95% CI 1.3–4.9) and serum bicarbonate levels (mean difference 3.4 mmol/L; 95% CI 1.9–4.9) at the end of follow-up (three months to five years) compared to those given placebo or conventional CKD treatment. When limited to studies reporting outcomes at one year, the positive effect of oral bicarbonate therapy on eGFR was attenuated. There were no significant treatment effects in other parameters such as systolic blood pressure (BP) and weight. These findings should be interpreted with caution and further trial evidence is needed to establish the net overall benefit or harm of oral bicarbonate therapy in CKD.
Bibliographical noteSupplementary Materials: The following are available online at www.mdpi.com/2077-0383/8/2/208/s1, Supplementary Figure S1. Forest plot comparing the effects of oral bicarbonate therapy and control on serum creatinine levels. Supplementary Figure S2. Forest plot comparing the effects of oral bicarbonate therapy and control on eGFR at one year. Supplementary Figure S3. Forest plot comparing the effects of oral bicarbonate therapy and control on serum bicarbonate levels at one year.
Funding: This work was supported by a National Institute of Health Research Health Technology Assessment (NIHR HTA) project grant (Ref: 10/71/10).
- acid-base balance
- SERUM BICARBONATE