Abstract and Introduction
Introduction: Patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) are at high risk of deep vein thrombosis (DVT) postoperatively, necessitating the use of prophylaxis medications. This investigation used a large claims database to evaluate trends in postoperative DVT prophylaxis and rates of DVT within 6 months after THA or TKA.
Methods: Truven Health MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases were reviewed from 2004 to 2013 for patients who underwent THA or TKA. Data were collected on patient age, sex, Charlson Comorbidity Index, and hypercoagulability diagnoses. Postoperative medication claims were reviewed for prescribed aspirin, warfarin, enoxaparin, fondaparinux, rivaroxaban, and dabigatran.
Results: A total of 369,483 patients were included in the analysis, of which 239,949 patients had prescription medication claims. Warfarin was the most commonly prescribed anticoagulant. Patients with a hypercoagulable diagnosis had markedly more DVTs within 6 months after THA or TKA. More patients with a hypercoagulable diagnosis were treated with warfarin or lovenox than other types of anticoagulants. A multivariate regression analysis was performed, showing that patients prescribed aspirin, fondaparinux, and rivaroxaban were markedly less likely than those prescribed warfarin or enoxaparin to have a DVT within 6 months after THA or TKA.
Conclusion: After THA and TKA, warfarin is the most commonly prescribed prophylaxis. Patients with hypercoagulability diagnoses are at a higher risk of postoperative DVT. The likelihood of DVT within 6 months of THA and TKA was markedly higher in patients treated with warfarin and lovenox and markedly lower in those treated with aspirin, fondaparinux, and rivaroxaban.
More than 1 million total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures are performed in the United States each year. Patients undergoing these procedures are at an increased risk of thromboembolic complications.[2–4] The most common complication is deep vein thrombosis (DVT) because patients are placed at a higher risk as a result of venous stasis with leg positioning, increased risk of endothelial injury, and aberrant activation of the clotting cascade.[4,5] Prophylaxis after THA and TKA is recommended by both the American Academy of Orthopaedic Surgeons and American College of Chest Physicians; however, no consensus exists on the optimal prophylactic regimen. Anticoagulation after THA or TKA can pose unique challenges because anticoagulation medications must balance the reduction in blood clot formation, with the risk of postoperative bleeding, hematoma formation, revision surgery, and infection.[7–10] The vitamin K antagonist warfarin has been shown to be effective in reducing the rate of proximal DVTs and pulmonary embolisms.[11,12] The major advantage of warfarin is that it can be reversed if bleeding complications arise or if patients require urgent surgical intervention.[13,14] Warfarin's most notable disadvantage is that it is only effective within a narrow therapeutic window, necessitating frequent laboratory monitoring and dose adjustments. These drawbacks have led to the use of alternative methods of chemoprophylaxis.
Recent studies have demonstrated the effectiveness of aspirin prophylaxis after TKA or THA. In a trial of 13,356 patients undergoing THA, low-dose aspirin reduced the rate of DVT by 29%, PE by 43%, and fatal pulmonary embolism by 58% compared with placebo. Low-molecular-weight heparin agents, such as enoxaparin, have also been shown to be effective; however, they must be administered through subcutaneous injection. Other therapies such as factor Xa and direct thrombin inhibitors are appealing because they can be delivered orally, do not require monitoring, and have constant dosing for most patients. Unfortunately, this group of medications is costly and requires fresh frozen plasma for reversal.[5,17,18]
Although DVT prophylaxis after THA and TKA is assumed to be the standard of care, given the high likelihood of thromboembolic events without prophylaxis, a paucity of data exists on surgeon practice patterns and changes over time. In addition, few studies have evaluated postoperative DVT rates by anticoagulants at a large-scale population level. The purpose of this investigation was to use a large claims database to evaluate trends over time in national practice patterns of postoperative DVT prophylaxis and rates of DVT within 6 months after THA or TKA procedures.
J Am Acad Orthop Surg. 2018;26(19):698-705. © 2018 American Academy of Orthopaedic Surgeons