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Abstract: FR-PO099

Metabolic Acidosis Increases the Risk of AKI in Critically Ill Patients: A Multicenter Cohort Study

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention


  • Inda-Filho, Antonio Jose, University Center ICESP, Brasília, Distrito Federal, Brazil
  • Ribeiro, Heitor S., University Center ICESP, Brasília, Distrito Federal, Brazil
  • Duarte, Marvery P., Universidade de Brasilia, Brasilia, Distrito Federal, Brazil

Acute kidney injury (AKI) is a common complication in critically ill patients admitted to the intensive care units (ICU), as well as metabolic acidosis, characterized by low levels of serum bicarbonate. However, the possible association between both is not clear yet. The aim of the present study was to evaluate metabolic acidosis as a risk factor for the development of AKI.


A prospective cohort study was conducted by collecting data from three ICUs in the Federal District, Brazil. The serum bicarbonate level in the first 24 hours after ICU admission was used to define the acid-base disorders; acidosis (<22 mEq/L) and alkalosis (>26 mEq/L). The KDIGO guideline for AKI was used to define it based on serum creatinine levels. The mortality outcome was followed up to 28 days during the ICU stay. Odds ratio and Cox regression were performed with corrections for age, male sex, serum creatinine, and the presence of any comorbidity.


A total of 2,732 patients (66±19 years and 55% men) were analyzed, with metabolic acidosis found in 26% (n=705) and metabolic alkalosis in 32% (n=865). Compared with the patients without acid-base disorders, those with acidosis were 81% more likely to develop AKI (OR=1.81; 95%CI:1.10–2.99), while those with alkalosis were 44% less likely (OR=0.56; 95%CI:0, 32–0.98). Both acidosis and alkalosis were not associated with increased risk of mortality (HR=1.03; 95% CI: 0.68–1.56 and 0.99; 95% CI: 0.68–1.42, respectively).


In critically ill ICU patients, metabolic acidosis, but not alkalosis, was associated with the development of AKI compared to the patients without acid-base disorders. On the other hand, metabolic alkalosis was a protective factor to the development of AKI. For the mortality outcome, none of the acid-base disorders was significantly associated with it.