Early versus late therapeutic plasma exchange in sepsis and septic shock: A retrospective observational study of 28-day mortality and biomarker trajectories.

Sepsis involves dynamic inflammatory and endothelial responses, and the timing of extracorporeal therapies such as therapeutic plasma exchange (TPE) may influence clinical outcomes. However, the optimal timing of TPE remains unclear. This retrospective single-center observational study included adult patients with sepsis or septic shock who underwent TPE in the intensive care unit between January 1, 2017 and August 1, 2025. Patients were categorized as early (≤ 48 hours after diagnosis) or late (> 48 hours). The primary outcome was 28-day mortality. Secondary analyses evaluated longitudinal changes in biomarkers and laboratory parameters. Eighty-eight patients were included (early n = 39; late n = 49). Overall 28-day mortality was 40.9% (36/88). Kaplan-Meier analysis demonstrated no significant difference in 28-day survival between the groups (log-rank P = .91). In multivariable Cox regression adjusted for Sequential Organ Failure Assessment and Acute Physiology and Chronic Health Evaluation II, TPE timing was not independently associated with 28-day mortality (hazard ratio 0.90, 95% confidence interval 0.44-1.83, P = .76). Across the overall cohort, significant temporal changes were observed in C-reactive protein and lactate dehydrogenase levels during TPE treatment. Early TPE initiation was not associated with improved 28-day survival. Observed biomarker trajectories should be interpreted cautiously given the retrospective design, limited sample size, and potential residual confounding.