Clinical question: Is aspirin as effective as low-molecular-weight heparin (LMWH) for thromboprophylaxis in patients with orthopedic trauma?
Background: Studies have outlined the benefits of thromboprophylaxis in patients with traumatic orthopedic injuries to prevent thromboembolic complications and death. Recent studies suggest aspirin may be an effective alternative to LMWH in patients who have undergone total joint arthroplasty. However, similar data in patients with orthopedic trauma is limited.
Study design: Pragmatic, multicenter, randomized, noninferiority trial
Setting: 21 adult trauma centers across the U.S. and Canada
Synopsis: 12,211 adult patients with an extremity fracture requiring operative management (excluding fractures of the hand or forefoot) or any pelvic or acetabular fracture regardless of management strategy were randomly assigned to receive aspirin thromboprophylaxis (81 mg twice daily orally) versus LMWH (30 mg twice daily subcutaneously, with flexibility in dosing based on weight, renal function, or other individual patient factors) while admitted. The duration of post-discharge therapy was left to the treating physician’s discretion. Results indicated noninferiority of aspirin versus LMWH in the prevention of all-cause mortality (0.78% versus 0.73%; 96.2% CI, -0.27 to 0.38; P <0.0001). The authors also found no difference in the secondary outcomes of pulmonary embolism, bleeding complications, wound complications, or surgical site infections. The 90-day incidence of deep-vein thrombosis (DVT) was 2.51% in the aspirin group versus 1.71% in the LMWH group (95% CI, 0.28 to 1.31). Notably, adherence to the prescribed regimen after discharge was greater for the aspirin group (94.4%) than the LMWH group (86.6%) with a median duration of 21 post-discharge days prescribed in both groups.
Previous studies indicate that patients strongly favor aspirin versus LMWH due to ease of administration and cost considerations. Hospitalists caring for patients with orthopedic trauma may now consider aspirin as an alternative to LMWH while acknowledging the increased incidence of DVT with this strategy.
Bottom line: Aspirin is non-inferior to LMWH in patients with orthopedic trauma for the prevention of all-cause mortality and pulmonary embolism.
Citation: Major Extremity Trauma Research Consortium (METRC); O’Toole RV, et al. aspirin or low-molecular-weight heparin for thromboprophylaxis after a fracture. N Engl J Med. 2023;388(3):203-13.
Dr. Sevov
Dr. Redman
Dr. Sevov and Dr. Redman are clinical assistant professors in the division of hospital medicine at The Ohio State University Wexner Medical Center in Columbus, Ohio. Disclosure: Dr. Sevov’s spouse receives consulting fees from Merck, AbbVie, and Eli Lilly.