Critical risks of haemoadsorption for COVID-19 patients and directions for future evaluations: a nationwide propensity score matched cohort study.

Haemoadsorption has been suggested as treatment adjunct for sepsis and septic shock, cardiac surgery, acute respiratory distress syndrome, and coronavirus disease 2019 (COVID-19). Randomised clinical trials did not provide conclusive evidence for benefits and even suggest risks in COVID-19 patients. Retrospective observational cohort study based on hospital remuneration data from all COVID-19 patients treated in intensive care units in Germany between 01/01/2020 and 12/31/2021. Regression modelling was performed for 1:1 propensity score matching of 2058 patients. Two-sided probability values for group comparisons and regression models with spline functions controlling for non-linear relationships and medically relevant interaction variables were calculated. In-hospital mortality of patients supported with haemoadsorption was significantly higher compared to matched control patients (74.6% vs. 70.3%, p = 0.0299). Haemoadsorption was associated with coagulopathy (68.0% vs. 54.9%, p < 0.0001), cardiac arrhythmia (49.2% vs. 44.2%, p = 0.0272), and cardiopulmonary resuscitation (CPR, 19.3% vs. 13.1%, p = 0.0002). Further, haemoadsorption increased the chance of death for COVID-19 patients without septic shock (odds ratio, OR [within a 95% confidence interval, CI]; 1.40 [1.05-1.86]) and did not improve survival of septic shock patients (1.19 [0.85-1.67]). Independent variables with a significant impact on mortality included the use of extracorporeal membrane oxygenation (ECMO, 2.15 [1.68-2.76]) and CPR (1.60 [1.03-2.45]). The timing of the haemoadsorption therapy had no effect on patients´ outcomes. Due to inconclusive evidence for benefit and potential harm, haemoadsorption therapy should be limited to thoroughly designed clinical trials before introduced into clinical routine in the context of COVID-19.