Breaking Down the Evidence: A Multicenter Analysis of Venous Thromboembolism Among Trauma Patients With Lower Extremity Fractures

OBJECTIVES: To determine whether chemoprophylaxis initiation within 24 hours reduces venous thromboembolism risk among trauma patients with lower extremity long bone fractures. METHODS: Design: This was a retrospective cohort study. Setting: 17 Level I trauma centers as a part of the Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study group. Patient Selection Criteria: Patients aged 18-40 years with a diagnosis of lower extremity long bone fracture between January 1, 2018 to December 31, 2020 were included. Outcome Measures and Comparisons: Primary outcome was VTE during admission. Patients were compared based on VTE chemoprophylaxis initiation within 24 hours (early prophylaxis, E-PROPH) versus not (late or no prophylaxis, L-PROPH) using inverse probability weighted Cox survival analysis. RESULTS: 120 (5.3%) among 2,264 patients with lower extremity fractures developed VTE. 57.5% received E-PROPH and 42.5% received L-PROPH. E-PROPH group had fewer patients with an injury severity score 16 (30.3% vs. 52.4%, p<0.001) and a lower proportion of associated head injury (8.1% vs. 26.7%, p<0.001). VTE incidence was significantly higher in L-PROPH group than in E-PROPH group (8.6% vs. 2.8%, p<0.001). In the adjusted model, E-PROPH was independently associated with nearly a half reduction in VTE incidence (hazard ratio: 0.54, 95% confidence interval: 0.34-0.85). There was no significant difference in the adjusted bleeding complications model (aOR 1.84, 95% CI 0.75, 4.57). CONCLUSION: VTE chemoprophylaxis within the first 24 hours of admission was associated with a marked reduction in VTE incidence among patients with traumatic lower extremity long bone fractures without increase in bleeding risks. LEVEL OF EVIDENCE: Level III: retrospective cohort study