Time series differences in coagulopathy in mechanically ventilated COVID-19 and bacterial pneumonia patients: a nationwide observational study in Japan.

Background: Severe acute respiratory syndrome coronavirus 2 infection causes systemic immune overresponse (cytokine storm), which can lead to microthrombi and dysfunction of coagulation such as disseminated intravascular coagulation (DIC) of sepsis. Coronavirus disease 2019 (COVID-19) coagulopathy is known to occur mainly in the pulmonary microcirculation. We aimed to investigate hematological differences in coagulopathy between COVID-19 pneumonia and bacterial pneumonia.

Methods: We performed an observational cohort study using the Japanese REsearch of COVID-19 by assEmbling Real-world data (J-RECOVER) study database for COVID-19 patients and the Japan Medical Data Center (JMDC) database for bacterial pneumonia patients. The J-RECOVER database includes data from patients discharged between January 1 and September 31, 2020. The JMDC database covers patients emergently hospitalized from 2014 to 2022. We analyzed the association between hematological coagulopathy, systematic inflammation, and organ dysfunction in both groups after one-to-one propensity score matching.

Results: We enrolled 572 COVID-19 patients and 2,413 bacterial pneumonia patients who required mechanical ventilation. The COVID-19 group was younger, had higher intensive care unit admission rates, and lower mortality in comparison to the bacterial group (p < 0.05). On day 1, the two groups showed no significant differences in JAAM-2 and sepsis-induced coagulopathy criteria. After matching, platelet counts, antithrombin activity, and prothrombin time-international normalized ratio were consistently maintained within normal ranges in the COVID-19 group. However, trends in D-dimer and fibrin degradation products in the COVID-19 group were similar to those in the bacterial pneumonia group.

Conclusions: COVID-19 coagulopathy differs from bacterial septic DIC by exhibiting lower platelet consumption and minimal vascular hyperpermeability. Consequently, management strategies for COVID-19 coagulopathy should be distinct from those for septic DIC.