Incidence and risk factors for venous thromboembolism in patients with nonsurgical isolated lower limb injuries

Purpose The aim of our study was to determine the incidence of venous thromboembolism (VTE) in patients with nonsurgical isolated lower limb injury and to determine the risk factors associated with the development of the condition. Methods This observational study was conducted in French hospital emergency departments (EDs). Patients older than 18 years presenting with nonsurgical isolated lower limb injury below the knee in the ED were included. Deep VTE was diagnosed with compression ultrasound. The final diagnosis of VTE was confirmed by an expert panel. Results Three thousand six hundred ninety-eight patients were included, and compression ultrasound examination was obtained in 2761 (75%) of them who were retained in the analysis. Deep venous thrombosis occurred in 177 patients and nonfatal pulmonary embolism in 1 patient. The incidence of VTE, mainly distal and asymptomatic, was 6.4% (95% confidence interval, 5.5%-7.4%). In a multivariate analysis, predictive variables of VTE were age of at least 50 years (odds ratio, 3.14; P < .0001), rigid immobilization (odds ratio, 2.70; P < .0001), no weight bearing (odds ratio, 4.11; P = .0015), and severe injury (odds ratio, 1.88; P = .0002). The discriminant analysis showed that age was the only variable independent of an antithrombotic prophylaxis associated with VTE. Conclusion The incidence of VTE was 6.4% in patients with nonsurgical lower limb injury. Rigid immobilization, recommendation not to bear weight, severe injury, and age of at least 50 years should be considered as risk factors for VTE. Emergency physicians should also take age into account when prescribing antithrombotic prophylaxis.