Thromboembolic events in hospitalised patients with COVID-19: ecological assessment with a scoping review

OBJECTIVES: Thrombosis is a common complication of the novel COVID-19. Pre-COVID-19 studies reported racial differences in the risk of developing thrombosis. This study aimed to describe the geographical variations in the reported incidences and outcomes of thromboembolic events and thromboprophylaxis in hospitalised patients with COVID-19. The final search for randomised clinical trials was carried out in January 2022. Screening eligible articles and data extraction were independently performed in duplicate by multiple reviewers. DESIGN: Scoping review. MEDLINE, Embase, Cochrane Libraries were searched using terms related to COVID-19 and thromboembolism. SETTING: Hospitals all over the world. PARTICIPANTS: In-hospital patients with COVID-19. OUTCOME MEASURES: The incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE), and the prophylactic anticoagulation therapy. RESULTS: In total, 283 studies were eligible, representing (239 observational studies, 39 case series and 7 interventional studies). The incidence of DVT was the highest in Asia (40.8%) and hospital mortality was high (22.7%). However, the incidence of PE was not very high in Asia (3.2%). On the contrary, the incidence of PE was the highest in the Middle East (16.2%) and Europe (14. 6%). Prophylactic anticoagulation therapy with low-molecular-weight heparin was the main treatment provided in all areas. Four of the seven randomised clinical trials were conducted internationally. CONCLUSIONS: The incidence of DVT was the highest in Asia. The incidence of PE was higher in the Middle East and Europe; however, detection bias during the pandemic cannot be ruled out. There were no major differences in the type or dose of prophylactic anticoagulants used for thromboprophylaxis among the regions.