Sepsis-associated acute kidney injury (SA-AKI) carries high mortality, particularly in patients with septic shock, where dysregulated cytokine release ("cytokine storm") drives hemodynamic collapse and multiorgan failure. While continuous kidney replacement therapy (CKRT) is widely used, increasing convection volume offers limited benefit in removing middle molecules. The oXiris filter enables adsorption of inflammatory mediators, but clinical evidence on patient outcomes remains inconclusive. We aimed to evaluate the effectiveness of oXiris hemoadsorption versus standard CKRT in patients with SA-AKI using propensity score matching (PSM).

We retrospectively identified adult patients with SA-AKI who received CKRT at Severance Hospital between 2010 and 2025. Before matching, 5,601 received standard CKRT and 54 received oXiris. 1:10 nearest-neighbor PSM was performed on age, sex, SOFA score, norepinephrine dose, lactate, and key comorbidities (ESRD, transplant, hematologic and solid malignancy), yielding 560 matched patients (oXiris n=54; control n=506). The primary outcome was in-hospital mortality; 7- and 28-day mortality were secondary. Survival was compared by Kaplan–Meier and Cox proportional hazards models.

After PSM, baseline characteristics were well balanced (all matching covariates showed standardized mean differences below 0.05; residual imbalance in non-matching variables was addressed in a doubly-robust sensitivity analysis.). In-hospital mortality showed no significant difference (HR 0.77; 95% CI 0.55–1.07; p=0.120), although the trend favored oXiris. 28-day mortality showed a near-significant trend (HR 0.74; 95% CI 0.52–1.04; p=0.084), and 7-day mortality (HR 0.74; 95% CI 0.50–1.11; p=0.149) was not significant.

oXiris use was not associated with a statistically significant reduction in short-term mortality, but the consistent direction of effect across all timepoints—particularly at 28 days—suggests potential clinical benefit. Larger prospective studies are warranted to identify subgroups who may benefit from adsorption-based therapies.