Temporal changes of hemostatic activity in patients hospitalized for COVID-19: a prospective observational study.

INTRODUCTION: Hemostatic abnormalities play an important role in the pathogenesis of COVID‑19 and are considered determinants of the patients' outcomes. Less is known about the dynamics of these abnormalities in a short‑term observation. OBJECTIVES: The aim of the study was to evaluate hemostatic activity markers in patients hospitalized for COVID‑19 depending on the severity of respiratory failure. PATIENTS AND METHODS: This was a prospective observational study enrolling adult patients hospitalized for COVID‑19 in a tertiary center in Poland, from January to May 2021. Blood samples were drawn upon admission and 28 days after the admission to measure the markers of coagulation, fibrinolysis, and endothelial dysfunction, and to evaluate whether there are significant differences between these 2 time points. All analyses were performed in the entire cohort and after stratification into 3 groups depending on the degree of respiratory support. RESULTS: We recruited 245 patients at the median age of 63 years (interquartile range, 52-69), among whom 158 (64.5%) were men. The analysis of hemostatic markers on admission revealed that hypercoagulability, hypofibrinolysis, and endothelial dysfunction are related to the degree of respiratory support. We found significant differences between the admission and 28‑day follow‑up in all markers except for plasminogen activity. Interestingly, the markers of endothelial dysfunction remained the highest in the advanced respiratory support group after 28 days, while differences in the other markers diminished. CONCLUSION: Hemostatic abnormalities are significantly attenuated within a month after a hospital admission due to COVID‑19. The initially observed association between severity of the disease and hemostatic derangements persists only for the markers of endotheliopathy.