SARS-CoV-2 is a member of the family of coronaviruses associated with severe outbreaks of respiratory diseases in recent decades and is the causative agent of the COVID-19 pandemic. The recognition by and activation of the innate immune response recruits neutrophils, which, through their different mechanisms of action, form extracellular neutrophil traps, playing a role in infection control and trapping viral, bacterial, and fungal etiological agents. However, in patients with COVID-19, activation at the vascular level, combined with other cells and inflammatory mediators, leads to thrombotic events and disseminated intravascular coagulation, thus leading to a series of clinical manifestations in cerebrovascular, cardiac, pulmonary, and kidney disease while promoting severe disease and mortality. Previous studies of hospitalized patients with COVID-19 have shown that elevated levels of markers specific for NETs, such as free DNA, MPO, and H3Cit, are strongly associated with the total neutrophil count; with acute phase reactants that include CRP, D-dimer, lactate dehydrogenase, and interleukin secretion; and with an increased risk of severe COVID-19. This study analyzed the interactions between NETs and the activation pathways involved in immunothrombotic processes in patients with COVID-19.

Background: Several easy-to-use risk scoring systems have been built to identify patients at risk of developing complications associated with COVID-19. However, information about the ability of each score to early predict major adverse outcomes during hospitalization of severe COVID-19 patients is still scarce. Methods: Eight risk scoring systems were rated upon arrival at the Emergency Department, and the occurrence of thrombosis, need for mechanical ventilation, death, and a composite that included all major adverse outcomes were assessed during the hospital stay. The clinical performance of each risk scoring system was evaluated to predict each major outcome. Finally, the diagnostic characteristics of the risk scoring system that showed the best performance for each major outcome were obtained. Results: One hundred and fifty-seven adult patients (55 ± 12 years, 66% men) were assessed at admission to the Emergency Department and included in the study. A total of 96 patients (61%) had at least one major outcome during hospitalization; 32 had thrombosis (20%), 80 required mechanical ventilation (50%), and 52 eventually died (33%). Of all the scores, Obesity and Diabetes (based on a history of comorbid conditions) showed the best performance for predicting mechanical ventilation (area under the ROC curve (AUC), 0.96; positive likelihood ratio (LR+), 23.7), death (AUC, 0.86; LR+, 4.6), and the composite outcome (AUC, 0.89; LR+, 15.6). Meanwhile, the inflammation-based risk scoring system (including leukocyte count, albumin, and C-reactive protein levels) was the best at predicting thrombosis (AUC, 0.63; LR+, 2.0). Conclusions: Both the Obesity and Diabetes score and the inflammation-based risk scoring system appeared to be efficient enough to be integrated into the evaluation of COVID-19 patients upon arrival at the Emergency Department.