Epidemiology of sepsis-associated acute kidney injury in the ICU with contemporary consensus definitions

BACKGROUND: The definition of sepsis-associated acute kidney injury (SA-AKI) was updated in 2023. This study aims to describe the epidemiology of SA-AKI using updated consensus definition and to evaluate clinical outcomes. METHODS: The study was a retrospective cohort analysis conducted at two academic medical centers. Adult patients admitted to intensive care units (ICU) between 2010 and 2022 were included and categorized as SA-AKI, sepsis alone, or AKI alone. SA-AKI was further classified by time of onset (early < 2 days from sepsis diagnosis vs. late 2-7 days following sepsis diagnosis) and presence of septic shock. Clinical outcomes included hospital mortality and major adverse kidney events (MAKE = death, kidney replacement therapy, or reduced kidney function from baseline) at discharge. RESULTS: 187,888 adult ICU patients were included, and SA-AKI was found in nearly half of sepsis patients and about 1 in 6 ICU admissions. 1 in 4 patients with SA-AKI died during hospitalization and 37.7% experienced at least one MAKE by hospital discharge. Compared to sepsis or AKI alone, SA-AKI was associated with higher mortality (adjusted HR 1.59; 95% CI 1.51-1.66) and higher odds of MAKE (adjusted OR 3.35; 95% CI 3.19-3.51). The early clinical phenotype of SA-AKI was most common, with incident AKI decreasing daily from sepsis onset. The presence of septic shock significantly worsened outcomes. CONCLUSIONS: Applying updated consensus definitions highlights the high prevalence of SA-AKI in the ICU and its significant associated morbidity and mortality. Outcomes differ based on clinical phenotypes, including the timing of SA-AKI onset and the presence of shock.