Venous thromboembolism prophylaxis in Asian patients with severe COVID-19: A prospective cohort study

Severe coronavirus disease 2019 (COVID-19) triggers various coagulation system and leads to the development of venous thromboembolism (VTE). The effectiveness of anticoagulant prophylaxis in preventing VTE in Thailand remains unknown. We aimed to determine the prevalence of symptomatic VTE in patients with severe COVID-19 who received a standard dose of anticoagulants and to evaluate the risk factors. Our prospective cohort study included patients with severe COVID-19 who received anticoagulant prophylaxis. VTE, bleeding events and mortality were monitored until 60 days after VTE prophylaxis initiation. Of the 250 study patients, pulmonary embolism was observed in 7.2% of patients. In a multivariate Cox regression model, endotracheal intubation [hazard ratio (HR) = 13.75; 95% confidence interval (CI) = 2.87–65.82; p = 0.001] and high D-dimer levels [HR = 1.052; 95% CI = 1.023–1.081; p < 0.001) were significantly associated with higher VTE risk within 60 days of VTE prophylaxis. Bleeding and major hemorrhage occurred in 35 (14%) and eight (3.2%) patients, respectively. These findings indicated that a standard dose of anticoagulant may not be sufficient for preventing thrombosis in patients who require intensive care. Further research on the appropriate dose is necessary.