Prevalence of thromboembolic events and status of prophylactic anticoagulant therapy in hospitalized patients with COVID-19 in Japan

Abstract

Introduction One of the most prominent and concerning complications associated with coronavirus disease 2019 (COVID-19) is venous and arterial thromboembolisms. The aim of the present study was to delineate the prevalence of thromboembolic events and the current status of prophylactic anticoagulation therapy in patients with COVID-19 in Japan. Methods Between February 1 and August 31, 2020, we performed a dual-center, retrospective cohort study based on data obtained from the medical charts of COVID-19 patients admitted to healthcare facilities in Japan. The primary outcome was any thromboembolic events, including pulmonary embolism (PE), deep vein thrombosis (DVT), myocardial infarction, ischemic stroke and other systemic thromboemboli. Results During the study period, we extracted 628 consecutive patients admitted for COVID-19. Prophylactic anticoagulant therapy was administered in 63 (10%) patients of whom 20 (31.7%) were admitted to the intensive care unit (ICU). Thromboembolic events occurred in 18 (2.9%) patients (14.3% of patients in ICU and 2.2% of patients in the general wards). DVT were detected in 13 (2.1%) patients, PE in 11 (1.8%), and both DVT and PE in 6 (0.96%). An increasing prevalence in thromboembolic events was noted with progression in clinical severity. Overall in-hospital mortality was 4.8%. Conclusions Prophylactic anticoagulation therapy was administered in only 10% of all hospitalized COVID-19 patients. The prevalence of any thromboembolic events was 2.9% in COVID-19 patients with most events occurring in severe and critical patients. Therefore, prophylactic anticoagulation therapy may be warranted in severe and critical patients but in asymptomatic to moderate patients the practice remains controversial.

The current status of thrombosis and anticoagulation therapy in patients with COVID-19 in Japan: From the CLOT-COVID study

“…In line with the previous studies [ 17 , 19 , 24 , 25 ], the present study from Japan showed a lower incidence of VTE in hospitalized patients with COVID-19 than that in the studies from Western countries [ 7 , 9 , 10 ]. The interpretation of the present results should be taken with caution because the number of patients that underwent imaging examinations was small, which may have been partly due to the difficulty in diagnosing VTE in patients with COVID-19 from the following perspectives: 1) the symptoms of COVID-19, such as fever, dyspnea, and tachypnea, mimic those of PE [ 26 ], 2) a major influence of COVID-19 on the hemodynamic status and oxygenation could mask the suspicion of VTE leading to imaging examinations, and 3) a high threshold for imaging examinations due to isolation [ 27 ].…”

Arterial and Venous Thrombosis Complicated in COVID-19: A Retrospective Single Center Analysis in Japan

“…So far, there is limited evidence about the incidence of thrombosis and the association of biomarkers in Japanese population, except a few (15)(16)(17)(18). The objective of the current study was to identify the risk factors for the development of thrombosis.…”

Prevalence and Clinical Characteristics of Proximal Deep Venous Thrombosis After a High-Density Coronavirus Disease 2019 Cluster in a Japanese Psychiatric Hospital

“…This prevalence of proximal DVT is relatively high compared with recent studies of Japanese patients with COVID-19, which reported an incidence rate of 0.6% for VTE and 1.9-2.9% for arterial and venous thrombotic events. 11- 13 The findings of the present study indicate that hospitalized psychiatric patients could be at higher risk of COVID-19-associated VTE than non-psychiatric patients. Schizophrenia and antipsychotics are known risk factors for VTE due to increased epinephrine release, increased activation of the markers of thrombogenesis, increased levels of antiphospholipid antibodies, and changes in serotonin metabolism in the platelets.…”

“…In the present study, the rate of proximal DVT was high among patients with moderate or severe COVID-19, supporting the findings of other studies in which the incidence of VTE was high in certain patient groups, such as those in intensive care unit, with severe COVID-19. 3,13,15 As reported previously, 16 fatal coagulation abnormalities in severe cases of COVID-19 may be an important risk factor for the occurrence of VTE.…”