Hemoperfusion and blood purification strategies in patients with COVID-19: A systematic review

Background: Coronavirus disease-19 (COVID-19) ranges from asymptomatic infection to severe cases requiring admission to the intensive care unit. Together with supportive therapies (ventilation in particular), the suppression of the pro-inflammatory state has been a hypothesized target. Pharmacological therapies with corticosteroids and interleukin-6 (IL-6) receptor antagonists have reduced mortality. The use of extracorporeal cytokine removal, also known as hemoperfusion (HP), could be a promising non-pharmacological approach to decrease the pro-inflammatory state in COVID-19. Methods: We conducted a systematic review of PubMed and EMBASE databases in order to summarize the evidence regarding HP therapy in COVID-19. We included original studies and case series enrolling at least five patients. Results: We included 11 articles and describe the characteristics of the populations studied from both clinical and biological perspectives. The methodological quality of the included studies was generally low. Only two studies had a control group, one of which included 101 patients in total. The remaining studies had a range between 10 and 50 patients included. There was large variability in the HP techniques implemented and in clinical and biological outcomes reported. Most studies described decreasing levels of IL-6 after HP treatment. Conclusion: Our review does not support strong conclusions regarding the role of HP in COVID-19. Considering the very low level of clinical evidence detected, starting HP therapies in COVID-19 patients does not seem supported outside of clinical trials. Prospective randomized data are needed.