Approach to the Treatment of Chronic Metabolic Acidosis in CKD

Chronic metabolic acidosis is not uncommon in patients with chronic kidney disease (CKD). Clinical practice guidelines suggest that clinicians administer alkali to maintain serum bicarbonate level at a minimum of 22 mEq/L to prevent the effects of acidosis on bone demineralization and protein catabolism. Small interventional studies support the notion that correcting acidosis slows CKD progression as well. Furthermore, alkaline therapy in persons with CKD and normal bicarbonate levels may also preserve kidney function. Observational studies suggest that targeting a serum bicarbonate level near 28 mEq/L may improve clinical outcomes above and beyond targeting a value ≥ 22 mEq/L, yet values > 26 mEq/L have been reported to be associated with incident heart failure and mortality in the CRIC (Chronic Renal Insufficiency Cohort) Study. Furthermore, correcting acidosis may provoke vascular calcification. This teaching case discusses several uncertainties regarding the management of acidosis in CKD, such as when to initiate alkali treatment, potential side effects of alkali, and the optimum serum bicarbonate level based on current evidence in CKD. Suggestions regarding the maximum sodium bicarbonate dose to administer to patients with CKD to achieve the target serum bicarbonate concentration are offered.