[What is confirmed in the treatment of metabolic acidosis in chronic kidney disease?].

Precise regulation of the acid-base balance is essential for the functioning of various organs and physiological processes. Acid retention and metabolic acidosis (MA) are frequent complications of chronic kidney disease (CKD) and can also occur following kidney transplantation. In addition to dietary modifications, pharmacological interventions, most notably sodium bicarbonate, are employed to correct MA. While several studies have reported a beneficial effect of MA correction on the progression of CKD, the results remain inconsistent and the magnitude of the treatment effect may be limited. Importantly, no beneficial effect on graft function has been demonstrated after kidney transplantation. The MA is associated with impaired bone quality and although alkali treatment has generally shown positive effects on markers of bone metabolism, consistent changes in bone density have not been observed. Additionally, MA is linked to an increased incidence of cardiovascular events but so far there is a lack of interventional studies with definitive cardiovascular endpoints. Sodium bicarbonate may lead to sodium retention, potentially increasing blood pressure, although the data on this are inconclusive. One interventional study with notable limitations reported a positive effect of alkali treatment on mortality. Correction of MA has been suggested to positively impact protein and muscle catabolism, although no improvement in physical performance was observed in a geriatric population. Limited studies exist on the endocrinological effects of alkali treatment but these indicate a favorable impact on glucose metabolism and potential benefits for thyroid function in predialysis CKD patients. Given the overall low to moderate level of evidence supporting the benefits of alkali treatment, the current guidelines from Kidney Disease: Improving Global Outcomes (KDIGO) propose alkali treatment to prevent serum bicarbonate levels < 18 mmol/l (prior < 22 mmol/l) in adults and the resulting complications.