Late Venous Thromboembolism Chemoprophylaxis and Increased Risk of Deep Venous Thrombosis, Pulmonary Embolism, and Mortality in Patients with Traumatic Spinal Injury.

Abstract

Optimal timing of venous thromboembolism chemoprophylaxis after traumatic spinal injury remains controversial due to bleeding concerns, particularly surrounding operative intervention. National-level mortality data evaluating delayed prophylaxis in this population are limited. We performed a retrospective cohort study of the 2021 National Trauma Data Bank including adult trauma patients with spinal injury and hospital length of stay longer than 48 hours (96,515). Patients were stratified by early (less than 48 hours; 63,051) vs late (48 hours or longer; 33,464) chemoprophylaxis. Primary endpoints were deep venous thrombosis, pulmonary embolism, and in-hospital mortality. Multivariate logistic regression adjusted for age, sex, mechanism, severe regional Abbreviated Injury Scale scores (spine, thorax, abdomen 3 or more), spine surgery, unplanned return to the operating room, and chemoprophylaxis type. Late chemoprophylaxis was associated with higher rates of deep venous thrombosis (3.5% vs 1.3%), pulmonary embolism (1.8% vs 0.8%), and mortality (5.4% vs 2.9%; all p < 0.0001). After adjustment, delayed prophylaxis remained independently associated with deep venous thrombosis (odds ratio [OR] 2.3, 95% CI 2.102 to 2.553), pulmonary embolism (OR 1.7, 95% CI 1.529 to 1.967), and mortality (OR 1.9, 95% CI 1.807 to 2.092; all p < 0.0001). Spine surgery was the strongest predictor of delayed initiation (OR 3.3, 95% CI 3.208 to 3.433). Increased thromboembolic risk with delayed prophylaxis persisted across operative, isolated spine injury, and spinal cord injury subgroups. In this national cohort of traumatic spinal injuries, chemoprophylaxis initiated 48 hours or longer after admission was independently associated with increased venous thromboembolism and mortality. These findings support early initiation when clinically feasible while highlighting the need for prospective evaluation of bleeding risk.