Impact of base excess on mortality in patients with sepsis-associated acute kidney injury: insights from US Intensive Care Unit Cohort.

backgroundSepsis often leads to acute organ dysfunction and significantly increases the risk of mortality, frequently occurring alongside acute kidney injury, termed sepsis-associated acute kidney injury (Sa-AKI). This study aimed to assess whether base excess (BE) is associated with mortality in Sa-AKI patients within the intensive care unit (ICU).

methodsData were extracted from a US ICU cohort. BE served as the exposure variable, and 30-day and 90-day ICU all-cause mortality were the outcomes of interest. Multivariate Cox proportional hazards models were performed to assess the associations of BE and mortality outcomes of interest among Sa-AKI patients. Furthermore, multivariate restricted cubic spline (RCS) analyses were used to investigate potential nonlinear relationships between BE and outcomes of interest.

result10,812 Sa-AKI patients were included, RCS analyses demonstrated a non-linear relationship between BE and the risk of mortality for both 30-day and 90-day ICU mortality. Multivariate Cox proportional hazards models indicated that higher BE groups had a decreased risk of 30-day (Q3: HR 0.79, 95%CI 0.69-0.91; Q4: HR 0.82, 95%CI 0.73-0.93), 90-day ICU all-cause mortality (Q3: HR 0.81, 95%CI 0.72-0.91; Q4: HR 0.84, 95%CI 0.75-0.94) compared with the lowest BE group. Based on RCS analysis, patients were regrouped by BE values (Group 1: ≤ - 4 mmol/L, Group 2: - 4 to 7 mmol/L, Group 3: ≥ 7 mmol/L) for Kaplan-Meier survival analysis. Group 2 had the lowest 30-day and 90-day ICU mortality rate (log-rank P < 0.0001).

conclusionIn ICU patients with Sa-AKI, there is a non-linear relationship between BE levels and 30-day and 90-day all-cause mortality. A moderate BE range (- 4 to 7 mmol/L) is associated with a protective effect, whereas both excessively high and low BE levels increase mortality risk.