Safety and Efficacy of Aspirin Compared to Enoxaparin Following Total Hip and Total Knee Arthroplasty Among Patients Who Have a History of Venous Thromboembolic Disease.

Introduction: Despite the broad utilization of aspirin as a venous thromboembolism (VTE) chemoprophylactic agent following total knee (TKA) and total hip arthroplasty (THA), few studies have evaluated its safety and efficacy in patients who had a history of VTE. This study sought to evaluate the safety and efficacy of aspirin relative to enoxaparin in high-risk total joint arthroplasty (TJA) patients.

Methods: An all-payer claims database was queried for primary, elective THA, and TKA patients from January 2015 to December 2021. Patients who had a history of VTE were divided based on receipt of either aspirin (ASA) or enoxaparin as VTE prophylaxis. In a 1:1 ratio, 1,429 THA and 2,864 TKA high-risk ASA patients were matched to high-risk enoxaparin patients on age, sex, race, and presence of pertinent comorbidities. Multivariable regression analyses accounted for potential confounders.

Results: After multivariable analyses, similar risk of pulmonary embolism (PE) (THA: adjusted odds ratio [aOR]: 0.85, 95% confidence interval [CI]: 0.26 to 2.76; TKA: aOR: 0.71, 95% CI: 0.38 to 1.32) and deep vein thrombosis (DVT) (THA: aOR: 1.12, 95% CI: 0.53 to 2.36) was observed in the ASA cohorts relative to the enoxaparin cohorts. TKA patients in the ASA cohort had a lower risk of DVT than those in the enoxaparin cohort (aOR: 0.57, 95% CI: 0.33 to 0.96). THA ASA patients demonstrated a reduced risk of stroke (aOR: 0.03, 95% CI: 0.00 to 0.73), while TKA ASA patients had a lower risk of acute blood loss anemia (aOR: 0.77, 95% CI: 0.66 to 0.88).

Conclusion: High-risk patients who received ASA demonstrated similar risk of PE and DVT, but decreased risk of bleeding-related and medical complications compared to patients who received enoxaparin. The utilization of ASA in high-risk patients was not associated with an increased risk of adverse outcomes.