Low incidence of thromboembolism in hospitalized COVID-19 patients despite a very low thromboprophylaxis rate in Thailand

ABSTRACT

Background: International guidelines recommend thromboprophylaxis for hospitalized coronavirus disease 2019 (COVID-19) patients due to high prevalence of thromboembolism (TE). However, thromboprophylaxis is uncommonly prescribed in Thailand. Aim(s) To determine the incidence of TE and the mortality rate of hospitalized COVID-19 patients in Thailand. Method(s) We retrospectively reviewed medical records of COVID-19 patients admitted to King Chulalongkorn Memorial Hospital between February 2020 and August 2021. Result(s) There were 7452 hospitalized COVID-19 patients with 460 (6.2%) intensive care unit (ICU) patients. The decision of thromboprophylaxis was based on the discretion of attending physicians. Only 85 (1.14%) patients received anticoagulants due to new TE without thromboprophylaxis (43;0.58%), thromboprophylaxis (36;0.48%) or preexisting conditions (6;0.08%). Of 43 newly identified TE, there were 33 (0.44%) venous TE and 10 (0.14%) arterial TE. Among 43 TE, 29 were treated in ICU with an estimated incidence of 6.3% (29 of 460). The incidence of TE in non-ICU patients was very low (0.2 %;14 of 6992). Of 36 receiving standard-dose enoxaparin thromboprophylaxis, 3 (8.3%) developed venous TE. The overall mortality rate was 1.7% (126 of 7452), while the mortality rate in patients with TE was as high as 41.3% (19 of 46). Compared to patients without TE, patients with TE had a substantially increased risk of death (odds ratio of 48.0, 95% confidence interval, 25.9, 89.0;p < 0.0001). Conclusion(s) The incidence of TE in hospitalized COVID-19 patients was lower than those reported from Western countries despite a very low thromboprophylaxis rate in Thailand. Routine thromboprophylaxis for hospitalized COVID-19 Thais may not be cost-effective. However, ICU patients were at higher risk of TE. Patients who developed TE were at greater risk for death.