Abstract
Background: COVID-19 infection is associated with a high risk of venous thromboembolism (VTE) events. VTE prophylaxis reduces the risk of these events. The optimal dose of VTE prophylaxis however remains uncertain. Objectives: To compare the incidence of VTE in patients treated with either standard dose VTE versus intermediate dose VTE prophylaxis. Methods: In this retrospective cohort study, we analyzed data from 1786 adult patients admitted into the hospital with polymerase chain reaction confirmed COVID-19 infection between April 2020 to September 2021. For analysis, patients were divided into 2 cohorts: either standard dose prophylaxis treatment group (patients who received either unfractionated heparin 5000units 3 times a day or enoxaparin 30-40 mg daily subcutaneously) or intermediate dose VTE prophylaxis group (patients received either unfractionated heparin 7500 units 3 times daily or enoxaparin 30-40 mg twice a day subcutaneously). The primary outcome was incidence of VTE events described as either deep vein thrombosis (DVT) or pulmonary embolism (PE). Secondary outcome was bleeding events. Results: During the study period, 398 (22%) patients were primarily treated with standard dose VTE prophylaxis, whereas 1388 (78%) patients were treated with intermediate dose VTE prophylaxis. There was a significantly higher incidence of venous thromboembolism events noted in the standard dose prophylaxis treatment group when compared with the intermediate dose prophylaxis group (25/398 (6.3%) vs 35/1388 (2.5%) P < .001, [Odds Ratio 2.6197, 95% confidence interval = 1.5482-4.4327]). Multivariable-adjusted logistic regression, adjusting for age, obesity, and smoking, with the intermediate dose prophylaxis treatment group as the referent category revealed higher odds for incident venous thromboembolism events in the standard dose prophylaxis group. There was no statistically significant difference in bleeding events between the 2 treatment groups (9 (2.3%) for standard dose prophylaxis group vs 46 (3.3%) for intermediate dose prophylaxis group P = .26). Conclusions: Among patients hospitalized with COVID-19 infection, patients receiving intermediate dose VTE prophylaxis experienced lower incident rates of venous thromboembolism events compared to those receiving standard dose VTE prophylaxis without a statistically significant increase in the risk of bleeding events.