Venous thromboembolism after orthopedic surgery: Implications of the choice for prophylaxis

IntroductionVenous thromboembolism (VTE) is an important cause of morbidity and mortality following major orthopedic surgeries. In clinical trials, fondaparinux and low molecular weight heparins have been shown to be more effective than unfractionated heparin (UFH) in preventing VTE. We retrospectively analyzed a large hospital discharge database to assess the occurrence of clinically detected VTE as a function of the injectable antithrombotic agent used for VTE prophylaxis in orthopedic surgery.MethodsThe Premier's Perspective database, representing over 500 hospitals across the US, was utilized to identify patients receiving dalteparin, enoxaparin, fondaparinux, or UFH following hip or knee replacement or hip fracture surgery between January 2003 and March 2005. The primary outcome was the proportion of patients in each cohort with a VTE, while secondary outcomes included VTE occurrence during index hospitalization, and proportion of patients with a VTE-associated hospital readmission.ResultsA total of 144,806 patients were included in the study. Significantly fewer fondaparinux patients experienced a VTE event (1.5%) compared to enoxaparin (2.3%), dalteparin (2.1%), and UFH (4.2%). After controlling for baseline covariates, the odds of experiencing a VTE was significantly higher for other treatments when compared to fondaparinux (odds ratios: dalteparin = 1.22 [95% CI: 1.01 to 1.46] p = 0.0370; enoxaparin = 1.39 [1.19 to 1.62], p < 0.0001; UFH = 1.98 [1.67 to 2.34], p < 0.0001). Significantly fewer fondaparinux-treated patients experienced an event during the index hospitalization or were readmitted for a VTE compared to other treatments.ConclusionsSimilar to clinical trial findings, patients receiving fondaparinux in this study experienced fewer VTE events following orthopedic surgeries.