Objective: To compare rates of post-operative VTE between patients who received aspirin-only versus anticoagulants after hip or knee arthroplasty, using data from a large US-based administrative database.
Methods: We identified 231,780 adults who underwent total knee arthroplasty and 110,621 who underwent total hip arthroplasty in 2009-2012 and who received pharmacologic VTE prophylaxis (aspirin or anticoagulant) within the first 7 days after surgery. We compared the risk of post-operative VTE between patients receiving aspirin-only vs. anticoagulants, controlling for clinical and hospital characteristics using multivariable logistic regression with propensity score adjustment.
Results: Aspirin-only prophylaxis was administered to 7.5% of patients after knee arthroplasty and 8.0% after hip arthroplasty. Post-operative VTE was diagnosed in 2,217 (0.96%) patients after knee arthroplasty and 454 (0.41%) after hip arthroplasty. Compared to anticoagulants, aspirin was not associated with a higher risk for post-operative VTE either after knee arthroplasty (adjusted odds ratio and 95% confidence interval [OR] 0.34 [0.24-0.48]) or hip arthroplasty (OR 0.82 [0.45-1.51]).
Conclusions: Aspirin was not commonly administered as the sole prophylactic agent after hip or knee arthroplasty in this study. Patients who received aspirin-only did not have higher rates of post-operative VTE than patients who received anticoagulants. This study supports the use of aspirin in selected patients undergoing arthroplasty.