Supplementary Material for: Does oXiris Matter? A Comparative Outcome Study in CRRT-Treated Septic ICU Patients

Background/Objectives: Sepsis and septic shock frequently lead to acute kidney injury (AKI) and the need for continuous renal replacement therapy (CRRT). The oXiris hemofilter has cytokine- and endotoxin-adsorptive properties that may improve outcomes, but evidence remains inconclusive. This study compared the clinical outcomes of septic intensive care unit (ICU) patients treated with CRRT using oXiris versus standard filters. Methods: We conducted a retrospective observational study at a tertiary ICU in Istanbul between January 2019 and June 2024. Adult septic patients requiring CRRT within 24 hours of ICU admission were included. Patients were treated with either oXiris or standard CRRT filters (M-100 / M-150) for ≥ 16 hours. The primary endpoint was ICU mortality; secondary endpoints included ventilator-free days (VFD), ICU length of stay, and trends in inflammatory and biochemical markers. Results: A total of 360 patients were analyzed (133 oXiris, 227 standard filters). Despite higher baseline Sequential Organ Failure Assessment (SOFA) scores, C-reactive protein (CRP), procalcitonin (PCT), and lactate in the oXiris group, ICU survival was significantly higher (61.7% vs. 48.9%, p = 0.019). After adjustment, oXiris use remained independently associated with improved survival (OR 1.68, 95% CI 1.09–2.60, p = 0.020). Total CRRT duration was markedly shorter in the oXiris group (56.4 vs. 107.4 hours, p < 0.001). VFD were similar between groups. Inflammatory markers (CRP, PCT) remained elevated in oXiris patients through day 5, while hemodynamic stabilization (lactate decline, norepinephrine reduction) was more pronounced. Platelet counts decreased in both groups without recovery. Conclusions: Our study demonstrated that patients with sepsis treated using the oXiris filter exhibited significantly higher ICU survival rates, despite higher mechanical ventilation duration and ICU length of stay. However, persistent elevations in CRP and PCT, along with thrombocytopenia, suggest that these markers may not fully reflect therapeutic response. While oXiris use was associated with reduced ICU mortality, further randomized trials are needed to confirm its efficacy and account for potential confounders.