Aspirin Compared with Anticoagulation to Prevent Venous Thromboembolism After Knee or Hip Arthroplasty: a Large Retrospective Cohort Study

Abstract

BACKGROUND: Although guidelines now allow the use of aspirin as an alternative to anticoagulants for venous thromboembolism prophylaxis after knee or hip arthroplasty, there is limited data on contemporary use and outcomes with aspirin. OBJECTIVE: To describe the use of pharmacologic thromboprophylaxis and to assess venous thromboembolic risk with aspirin compared with anticoagulation after knee or hip arthroplasty. DESIGN: Retrospective cohort study using data from the US MedAssets database. PATIENTS: Adults with a principal discharge diagnosis of knee or hip arthroplasty between January 1, 2013, and December 31, 2014. MAIN MEASURES: We identified charges for medications used for thromboprophylaxis within 7 days after the index surgery from billing records. The primary outcome was postoperative venous thromboembolism identified by International Classification of Diseases, 9th edition codes, from the index hospitalization, rehospitalization within 30 days, or during an outpatient visit within 90 days postoperatively. We compared postoperative thromboembolic risk in patients receiving aspirin-only and those receiving anticoagulants using propensity score-adjusted multivariable logistic regression models. KEY RESULTS: We identified 74,234 patients with knee arthroplasty and 36,192 with hip arthroplasty who received pharmacologic thromboprophylaxis. Aspirin-only was used in 27.9% of all patients, while 24.2% and 24.1% received warfarin or enoxaparin as prophylactic monotherapy, respectively. Postoperative venous thromboembolism occurred in 495 (0.67%) patients undergoing knee arthroplasty and 145 (0.40%) undergoing hip arthroplasty. Aspirin-only was not related to increased odds of postoperative venous thromboembolism compared with anticoagulants in multivariable adjusted analyses (odds ratio [OR] 0.70; 95% confidence interval [CI], 0.56-0.87, and OR 0.93; 95% CI, 0.62-1.38 for knee or hip arthroplasty, respectively). CONCLUSIONS: More than a fourth of all patients received aspirin as the sole antithrombotic agent after knee or hip arthroplasty. Postoperative thromboprophylaxis with aspirin-only was not associated with a higher risk of postoperative venous thromboembolism compared with anticoagulants after hip or knee arthroplasty.

Aspirin for Postoperative Venous Thromboembolism Prophylaxis

“…We read with great interest the extremely informative paper recently published in this Journal by Baumgartner and colleagues, 1 demonstrating that postoperative thromboprophylaxis with aspirin-only was not associated with a higher risk of postoperative venous thromboembolism (VTE) compared with anticoagulants after hip or knee arthroplasty. Although various risk factors for VTE have been considered, the influence of systemic immunoinflammatory disease (such as psoriasis) and tuberculosis has not.…”

Aspirin thromboprophylaxis in joint replacement surgery

“…Use of aspirin for prevention of VTE following THA and TKA has gained popularity, especially among orthopedic surgeons, due to a low risk of surgical bleeding. 3 , 4 Both the American College of Chest Physicians and the American Academy of Orthopedic Surgeons (AAOS) support the use of aspirin‐only regimens for prevention of postoperative VTE over no pharmacologic prophylaxis. 1 , 5 AAOS, in particular, recommends stratification of patients into low‐ and high‐risk groups with regards to VTE, based on prior history of VTE, body mass index (BMI), active cancer, and cardiovascular risk factors, such as diabetes mellitus, coronary and cerebrovascular disease, and congestive heart failure.…”

“…As a result, a significant proportion of patients undergoing joint replacement surgery in the United States receive aspirin for postoperative VTE prophylaxis without any anticoagulants. 4 , 6 The majority of the data supporting this strategy come from retrospective studies that suggest that aspirin may be noninferior to anticoagulants as prophylaxis. 4 , 7 , 8 …”

“… 4 , 6 The majority of the data supporting this strategy come from retrospective studies that suggest that aspirin may be noninferior to anticoagulants as prophylaxis. 4 , 7 , 8 …”

Capsule Commentary on Baumgartner et al., Aspirin Compared with Anticoagulation to Prevent Venous Thromboembolism after Knee or Hip Arthroplasty: a Large Retrospective Cohort Study

“…B aumgartner et al examined the prophylactic practices of elective primary hip and knee arthroplasties over 2 years, comparing aspirin with other pharmacologic agents in preventing venous thromboembolism (VTE). 1 As might be expected, based upon the most recent American College of Chest Physician (ACCP) guidelines that includes aspirin (ASA) as an acceptable pharmacologic alternative in VTE prophylaxis, use of aspirin in this patient population has increased over time. 2 And despite this increase in postoperative joint patients receiving aspirin only (vs. other agents), no increase in clinically significant venous thromboembolism was identified out to 90 days.…”