Mortality and Kidney Function Recovery in Patients with Sepsis-Associated AKI vs. Nonseptic AKI Treated with Continuous Kidney Replacement Therapy

Background: It was recently suggested that sepsis-associated AKI (SA-AKI) is characterized by different pathogenesis and outcomes compared to non-Septic AKI (NS-AKI). We aim to examine risk factors and outcomes of SA-AKI vs NS-AKI among critically ill patients who developed AKI requiring renal replacement therapy (RRT). Methods: We performed a single-center retrospective analysis, including patients admitted to ICU who developed AKI requiring RRT at Policlinico of Bari (Jan. 2021 to July 2023). We classified patients in NS-AKI and SA-AKI groups based on the leading cause of AKI. The primary outcome was to assess mortality and kidney functional recovery (KFR) rate between SA-AKI and NS-AKI groups. 28-day survival probability was analyzed using the Kaplan–Meier method. Risk factors associated with in-hospital mortality were evaluated using Cox regression models. Results: 320 patients were included in the study; 131 patients developed SA-AKI (40.9%), while the remaining 189 were classified as NS-AKI (59.1%). 268 patients (83.8%) developed AKI Stage 3 and 40 patients AKI stage 2 (12.5%). There was no significant difference in CRRT duration and median lenght of ICU stay. The timing of CRRT initiation from ICU admission was late in the SA-AKI group (3 vs 1 days, p=0.002). 184 patients (57.5%) died at 28 days, with a higher percentage in the SA-AKI (70.2 vs 48.6%, p<0.001)(Figure 1). In-hospital mortality was reported in 221 patients (69%), with impressive percentages in the SA-AKI group (82.45 vs 69.3%, p<0.001). KFR was significantly higher in the NS-AKI (28.5% vs 13.7%, p=0.002). Median time of KFR was similar between groups (p=0.833). Multivariate Cox Regression analysis showed that only SA-AKI (HR 1.442, 95%CI 1.052-1.978, p=0.023) was independently associated with mortality risk. Conclusion: SA-AKI was associated with high mortality rate and lower likelihood of renal recovery compared to NS-AKI in critically ill patients requiring RRT.Clinical outcomes between SA-AKI and NS-AKI groups