D-Dimer Values and Venous Thromboembolism in Patients With COVID-19 in Japan　― From the CLOT-COVID Study ―

Background: To date, there are no large-scale data on the association between D-dimer levels at admission and the occurrence of venous thromboembolism (VTE) in Japanese patients with coronavirus disease 2019 (COVID-19). Methods and Results: The CLOT-COVID study was a retrospective, multicenter cohort study enrolling consecutive hospitalized patients with COVID-19 across 16 centers in Japan from April 2021 to September 2021. Among 2,894 enrolled patients, 2,771 (96%) had D-dimer levels measured at admission. Patients were divided into 3 groups based on tertiles of D-dimer levels at admission (1st tertile, D-dimer ≤0.5 μg/mL, n=949; 2nd tertile, D-dimer 0.51–1.09 μg/mL, n=894; 3rd tertile, D-dimer ≥1.1 μg/mL, n=928). The higher the tertile group, the more severe the COVID-19 status at admission. The incidence of VTE during hospitalization was highest in the 3rd tertile group (1st tertile, 0.3%; 2nd tertile, 0.3%; 3rd tertile, 3.6%; P<0.001). Even after adjusting for confounders in the multivariable logistic regression model, the higher D-dimer levels in the 3rd tertile (≥1.1 μg/mL) were independently associated with a higher risk of VTE during hospitalization (adjusted odds ratio 4.83 [95% confidence interval 1.93–12.11; P<0.001]; reference=1st tertile). Conclusions: Higher D-dimer levels at admission were associated with a higher risk of VTE events during hospitalization in Japanese patients with COVID-19. This could be helpful in determining patient-specific anticoagulation management strategies for COVID-19 in Japan.