When should I consider bicarbonate (BC) replacement in my patient with renal insufficiency?

Metabolic acidosis is one of the earliest complications of chronic kidney disease (CKD), with a direct correlation between the decline in glomerular filtration rate (GFR) and reduction in serum BC1.

Epidemiologic studies in patients with CKD have reported an independent association between serum BC (<22 meq/L considered low) and adverse renal outcomes and mortality1. Limited data from small interventional trials of alkali therapy supplementation and dietary interventions (eg, increased fruit and vegetable intake) have shown the benefits of raising serum BC. Specifically, 1 study involving patients with CKD stages 4 and 5 and another involving CKD stage 2 hypertensive nephropathy reported slower decline in creatinine clearance/eGFR in patients receiving BC replacement2,3.  

Less is known on the potential benefit of BC replacement in patients with acute kidney injury (AKI) with a recent Cochrane review finding no randomized controlled trials4 and national guidelines not recommending either in favor or against its use AKI5. Of note, BC therapy has also been associated with sodium and fluid overload, an increase in lactate and PCO2, and a decrease in serum ionized calcium6.

References

  1. Dobre M, Rahman M, Hostetter TH. Current status of bicarbonate in CKD. J Am Soc Nephrol 2015;26:515-523.
  2. de Brito-Ashurst I, Varagunam M, Raftery MJ, et al. Bicarbonate supplementation slows progression of CKD and improves nutritional status. J Am Soc Nephrol 2009; 20: 2075–2084.
  3. Mahajan A, Simoni J, Sheather SJ, et al. Daily oral sodium bicarbonate preserves glomerular filtration rate by slowing its decline in early hypertensive nephropathy. Kidney Int 2010;78: 303–309.
  4. Hewitt J, Uniacke M, Hansi NK, et al. Sodium bicarbonate supplements for treating acute kidney injury. Cochrane Database of Systematic Reviews 2012; Jun 13; (6):CD009204. doi: 10.1002/14651858.
  5. Palevsky PM, Liu KD, Brophy PD, et al. KDOQI US commentary on the 2012 KDIGO clinical practice guideline for acute kidney injury. Am J Kidney Dis 2013;61:649-72.
  6. Sabatini S, Kurtzman NA. Bicarbonate therapy in severe metabolic acidosis. J Am Soc Nephrol 2009;20:692-695.

 

Contributed in part by Cynthia Cooper, MD, Mass General Hospital, Boston, MA.

When should I consider bicarbonate (BC) replacement in my patient with renal insufficiency?

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