Metabolic Acidosis Might Worsen Kidney Outcomes in Patients with Stage 3-5 CKD

Identification of additional modifiable risk factors is necessary to develop new treatment strategies for CKD. Therefore, Dr Navdeep Tangri and his team conducted a study to quantify the association of metabolic acidosis with CKD progression and mortality in a large U.S. community-based cohort.

It was a longitudinal, retrospective cohort study of 51,558 non-dialysis-dependent patients with stage 3‒5 CKD from Optum's de-identified integrated electronic health records. The researchers selected cohorts of patients with confirmed metabolic acidosis or normal serum bicarbonate levels based on 2 consecutive serum bicarbonate values: 12 to < 22 mEq/L or 22-29 mEq/L, respectively, 28‒365 days apart. The major outcome assessed was ≥ 40 % decline in estimated glomerular filtration rate (eGFR), renal replacement therapy (chronic dialysis or kidney transplant), or all-cause mortality (DD40). The researchers also assessed each component of the composite outcome.

Key findings of the study were:

Upon analysis, the researchers found that the unadjusted 2-year incidence of adverse renal and fatal outcomes was significantly worse among patients in the metabolic acidosis group than those who had normal serum bicarbonate levels:

• 48 % vs 17 % for DD40,

◊ 10 % vs 4 % for ≥ 40 % decline in eGFR,

◊ 20 % vs 6 % for renal replacement therapy, and

◊ 31 % vs 10 % for all-cause mortality.

• Over ≤ 10-year period, for each 1-mEq/L increase in serum bicarbonate, they noted that the adjusted hazard ratio for DD40 was 0.926.
• For ≤ 2-year period, they noted that the adjusted odds ratio for DD40 was 0.873.

The authors concluded, "In this large community cohort of patients with stage 3‒5 CKD, the presence of metabolic acidosis was a significant, independent risk factor for the composite adverse outcome of CKD progression, renal replacement therapy, and all-cause mortality (DD40)."

For further information:

DOI: https://doi.org/10.1186/s12882-021-02385-z