Analysis of venous thromboprophylaxis duration and outcomes in orthopedic patients

Background: Venous thromboembolism (VTE) following total hip replacement (THR) and total knee replacement (TKR) surgery imposes significant health and economic burden. Objective: To examine the impact of thromboprophylaxis duration on deep vein thrombosis (DVT), pulmonary embolism (PE), total VTE (DVT and PE), and bleeding events among THR/TKR patients. Methods: A retrospective study (April 1, 2004, to December 31, 2006) was conducted using a US health plan claims database linked to an inpatient database containing medication use. Outcomes were compared using χ² tests; predictors of outcomes were analyzed using multivariate logistic regression. Results: Of 3497 patients, 3195 (91%) received thromboprophylaxis for ≥1 day postsurgery. Most patients (67%) received short-duration (1-14 days) rather than extended-duration (>14 days) thromboprophylaxis. The incidence of thromboembolic and bleeding events was higher in those who received short-duration thromboprophylaxis: DVT (2.84% vs 1.24%; P = .0038), PE (1.12% vs 0.19%; P = .0052), total VTE (3.96% vs 1.43%; P <.0001), and major bleeding (1.68% vs 0.38%; P = .0011). Multivariate logistic regressions (adjusted for observed demographic and clinical characteristics) revealed similar results. Baseline comorbidity score was significantly associated with major bleeding; most of the bleeding events in those who received short-duration thromboprophylaxis occurred within the first 14 days. Conclusions: In this database analysis of patients who had undergone THR/TKR surgery, a large proportion of patients did not receive the minimum duration of thromboprophylaxis recommended by the guidelines. Extended-duration thromboprophylaxis was associated with a significantly lower risk of DVT, PE, and VTE compared with short-duration thromboprophylaxis.