Urinary electrolyte parameters in sepsis-associated acute kidney injury: A prospective observational study

Sepsis-associated acute kidney injury (SA-AKI) significantly contributes to morbidity and mortality. Current biomarkers have limitations, necessitating the exploration of alternative indicators. This study aims to evaluate various urinary electrolyte parameters to predict SA-AKI.

A prospective observational study included 111 sepsis patients within 24 h of admission. Urinary electrolyte samples were collected, and indices were calculated. Patients were monitored for 7 days to assess for acute kidney injury (AKI) according to Kidney Disease Improving Global Outcomes (KDIGO) definition criteria, mortality rates, and the need for renal replacement therapy. Mann-Whitney U test and Chi-squared test were used to analyse continuous and categorical variables, respectively. Receiver-operating characteristic (ROC) curves were constructed to determine to discriminatory ability of various parameters in predicting AKI.

Of 111 patients, 42.3% developed AKI, with a mortality rate of 59.5%. When evaluating urinary parameters, the product of urine sodium and urine creatinine exhibited the maximum full form [area under the receiver operating characteristic (AUROC): 0.66; 95%CI: 0.56, 0.77)], and the parameter of fractional excretion of potassium (FeK) exhibited an AUROC of 0.62 (95%CI: 0.51, 0.72). Furthermore, 2-hour excretion of potassium revealed a statistically significant correlation with 2-hour creatinine clearance (r = 0.62, P < 0.001). Logistic regression models, incorporating Sequential Organ Failure Assessment (SOFA) score, FeK, and urine sodium concentration as variables (P = 0.020, 0.044, and 0.033, respectively), achieved an AUROC of 0.751 in predicting AKI.

Urine sodium levels and fractional potassium excretion moderately effectively predict AKI in sepsis patients. Urine potassium excretion correlates with glomerular filtration rate.