Improved Survival beyond 28 Days up to 1 Year after CytoSorb Treatment for Refractory Septic Shock: A Propensity-Weighted Retrospective Survival Analysis

Background and aims: It is currently unknown whether CytoSorb treatment for septic shock improves long-term survival beyond 28 days from intensive care unit (ICU) admission and which factors determine outcome.

Methods: This was a long-term follow-up retrospective analysis of patients with septic shock who were treated with continuous renal replacement therapy (CRRT) + CytoSorb (n = 67) or CRRT alone (n = 49). These patients were previously analyzed for 28-day mortality. The primary outcome was the time to long-term all-cause mortality. Factors associated with time to event were analyzed both weighted by stabilized inverse probability of treatment weights (sIPTW) as well as unweighted stratified by therapy received.

Results: The median follow-up for the total cohort was 30 days (interquartile range [IQR]: 5-334, maximum 1,059 days) after ICU admission and 333 days (IQR: 170-583) for those who survived beyond 28 days (n = 59). Survival beyond 28 days was sustained up to 1 year after ICU admission for both treatment regimens: 80% (standard error [SE] 7%) vs. 87% (SE 7%), for CytoSorb vs. CRRT, respectively, p = 0.853. By sIPTW, CytoSorb was significantly associated with long-term outcome compared to CRRT (adjusted hazard ratio [aHR] 0.59, 95% confidence interval [CI] 0.37-0.93, p = 0.025). Independent factors associated with long-term outcome in CytoSorb-treated patients were baseline log10 lactate levels (aHR 5.1, p = 0.002), age in the presence of comorbidity (aHR 2.60, p = 0.013), and presence of abdominal sepsis (aHR 0.34, p = 0.004). A lactate level above 6.0 mmol/L at the start of CytoSorb therapy had a positive predictive value of 79% for mortality (p = 0.013).

Conclusions: Survival is achieved with CytoSorb and CRRT for patients with septic shock beyond 28 days from ICU admission and may be improved for CytoSorb treatment. Lactate levels above 6.0 mmol/L at the start of CytoSorb therapy are predictive of worse outcome with high specificity and positive predictive value.