Anticoagulation bridging therapy patterns in patients undergoing total hip or total knee replacement in a us health plan: Real-world observations and implications

Background: The necessity for anticoagulant bridging therapy after joint replacement surgery is widely understood, but treatment administration patterns in the prevention of venous thromboembolism (VTE) after total hip replacement (THR) or total knee replacement (TKR) surgery during the hospital stay have yet to be examined. Objective: To investigate anticoagulation thromboprophylaxis patterns, especially the use of anticoagulant bridging therapy and/or nonbridged treatment strategies, in patients undergoing THR/TKR surgery. Methods: This retrospective study was based on a large hospital database linked with outpatient claims from 2005 through 2007. The study population included 1770 patients who were admitted for either THR or TKR surgery and were aged ≥18 years on the date of the surgery, defined as the index date. Patients were required to have commercial insurance or Medicare coverage and be continuously enrolled in their health plan for at least 180 days before and 90 days after the index date. The data were analyzed retrospectively for riskadjusted postsurgery VTE and major bleeding events among patients receiving anticoagulation thromboprophylaxis. Patterns of anticoagulant bridging therapy use were also assessed. A risk adjustment was performed using propensity score matching. Results: Of 1770 eligible patients, 1551 (88%) received anticoagulant VTE prophylaxis; 264 (15%) received combination low-molecular-weight heparin and warfarin. Of these, 105 (40%) patients were switched between the 2 monotherapies, and 159 (60%) received bridged (overlapping) prophylaxis. The overall rates of VTE and bleeding events were significantly lower with bridged therapy than with nonbridged therapy (5.8% vs 18.4%, respectively, for VTE, P <.02; 2.3% vs 4.60% for major bleeding, P =.41; 1.15% vs 8.05% for minor bleeding, P <.03). Conclusion: Although existing guidelines recommend anticoagulant bridging therapy after THR or TKR surgery, the limited data regarding anticoagulant bridging practice patterns suggest that patients who undergo such surgery do not receive adequate anticoagulant thromboprophylaxis immediately after discharge. Our findings suggest that increased use of bridging therapy after THR or TKR surgery may help improve postsurgery patient outcomes by reducing VTE and bleeding rates.