Investigating the association between IL-6 antagonist therapy and blood coagulation in critically ill patients with COVID-19: a protocol for a prospective, observational, multicentre study

Hypercoagulation is one the main features of COVID-19. It is induced by the hyperinflammatory response that shifts the balance of haemostasis towards pro-coagulation. Interleukin-6 (IL-6) antagonist therapy has been recommended in certain subgroups of critically ill patients with COVID-19 to modulate inflammatory response. The interaction between immune response and haemostasis is well recognised. Therefore, our objective is to evaluate whether the modulation of the inflammatory response by IL-6 antagonist inflicts any changes in whole blood coagulation as assessed by viscoelastic methods in critically ill patients with COVID-19.In this prospective observational study, we are going to collect data on inflammatory parameters and blood coagulation using the ClotPro® device. The primary outcome is the change of the fibrinolytic system measured by the Lysis Time and Lysis onset time before and after immunomodulation therapy. Data will be collected before the IL-6 antagonist administration at baseline (T0) then after 24, 48 hours, then on day 5 and 7 (T1-4, respectively). Secondary outcomes include changes in other parameters related to inflammation, blood coagulation and biomarkers of endothelial injury.Ethical approval was given by the Medical Research Council of Hungary (1405-3/2022/EÜG). All participants provided written consent. The results of the study will be disseminated through peer-reviewed journals.NCT05218369; Clinicaltrials.gov.