Low sodium to potassium ratio in spot urine sample is associated with progression to acute kidney injury and mortality in hospitalized patients with cirrhosis

Dig Liver Dis. 2021 Jan 11:S1590-8658(20)31199-3. doi: 10.1016/j.dld.2020.12.117. Online ahead of print.

ABSTRACT

BACKGROUND: sodium to potassium ratio in spot urine sample (Na/K_ur) is a surrogate marker of sodium excretion that is recommended for the management of patients with ascites due to cirrhosis.

AIMS: to investigate Na/K_ur ratio and fractional excretion of sodium (FENa) in patients admitted with decompensated cirrhosis, evaluating its relationship with acute kidney injury (AKI) and prognosis.

METHODS: prospective cohort study included 225 adult subjects. Urine samples were obtained within 48 h of hospitalization.

RESULTS: AKI at admission was observed in 32.9% of patients and was associated with lower Na/K_ur ratio, but not FENa. Among 151 subjects initially without kidney dysfunction, AKI at some point during hospitalization occurred in 26.2% and was independently associated with low Na/K_ur ratio at admission. AKI was observed in 44% of the patients with Na/K_ur ratio < 1 and only in 8% when values ≥ 2. Na/K_ur ratio at admission was independently associated with 30-day mortality, with Kaplan-Meier survival probability of 78.8% for Na/K_ur ratio < 1 and 93.6% for values ≥ 1.

CONCLUSIONS: low Na/K_ur ratio in spot urine sample is associated with progression to AKI and lower short-term survival in patients hospitalized for decompensated cirrhosis.

PMID:33446446 | DOI:10.1016/j.dld.2020.12.117