What are the benefits and risks of sodium bicarbonate in the treatment of chronic metabolic acidosis in patients with chronic kidney disease (CKD)?

Updated: Oct 10, 2018
  • Author: Christie P Thomas, MBBS, FRCP, FASN, FAHA; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

The choice of sodium bicarbonate dose remains unclear, and there are concerns over side effects, most notably fluid retention, especially with higher doses. Consequently, Abramowitz and colleagues conducted a single-blinded pilot study in 20 adults with stages 3 and 4 CKD and mild metabolic acidosis. Participants were treated during successive 2-week periods with placebo followed by escalating doses of oral sodium bicarbonate at 2-week intervals (0.3, 0.6, and 1.0 mEq/d per kg ideal body weight). [13]

Sodium bicarbonate was well tolerated, even at high doses; produced a dose-dependent increase in serum bicarbonate; and was associated with an improvement in lower extremity muscle strength and reduced urinary nitrogen excretion. The authors caution, however, that the results require further study and confirmation from a large randomized placebo-controlled study. [13]

In older persons with CKD, existing evidence is insufficient to show whether any benefits of sodium bicarbonate therapy outweigh the adverse effects and treatment burden in this population, which may include fluid retention and blood pressure from the additional sodium load, as well as gastrointestinal side effects. Trials of bicarbonate therapy for older persons with CKD are currently in progress. [15]

Metabolic acidosis in patients with CKD can also be treated with dietary modification. Dietary acid reduction can be accomplished by limiting the intake of acid-producing foods such as animal protein and emphasizing base-producing foods such as fruits and vegetables. [20]

In a year-long randomized study of 71 patients with stage 4 CKD, Goroya et al compared the effectiveness of daily oral sodium bicarbonate with that of base-producing fruits and vegetables for reduction of kidney injury and improvement of metabolic acidosis. Patients consuming fruits and vegetables dosed to reduce dietary acid by half had a reduction in kidney injury and improvement in metabolic acidosis comparable to that in the sodium bicarbonate group and did not experience hyperkalemia. [14]

The investigators note that study patients were selected to be at low risk for hyperkalemia and advise that caution should be exercised in prescribing fruits and vegetables in patients with very low estimated glomerular filtration rates. Nevertheless, Goroya et al concluded that treating metabolic acidosis in individuals with stage 4 CKD due to hypertensive nephropathy with fruits and vegetables appeared to be an effective kidney-protective adjunct. [14]


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