Aspirin Noninferior to Low-Molecular-Weight Heparin for Preventing Death in Patients with Fractures

Jessica Ganga

Although current clinical guidelines recommend low-molecular-weight heparin for thromboprophylaxis following a fracture, little is known about its efficacy when compared to aspirin, which is less expensive and easier to attain compared to low-molecular-weight heparin.1

Enter the Major Extremity Trauma Research Consortium investigators, who found in their multicenter, randomized, noninferiority trial that aspirin with thromboprophylaxis was as effective as using low-molecular-weight heparin in the prevention of death in patients who are hospitalized with a bone fracture.1

“We expect our findings from this large-scale trial to have an important impact on clinical practice that may even alter the standard of care," said Robert V. Toole, MD, the Hansjörg Wyss Medical Foundation Endowed Professor in Orthopaedic Trauma at the University of Maryland School of Medicine and Chief of Orthopaedics at the R Adams Cowley Shock Trauma Center at the University of Maryland Medical Center, in a press release.2

The study—a multidisciplinary collaboration between orthopedic surgeons and trauma surgeons—included 12,211 patients who were aged 18 years or older and had a fractured extremity or any pelvic or acetabular fracture.

Patients were randomly selected to receive aspirin (n = 6101) or low-molecular heparin (n = 6101). Of the total, 0.7% had a history of venous thromboembolism and 2.5% had a history of cancer. Once patients were discharged from the hospital, they were prescribed a median 21-day dose of thromboprophylaxis in addition to receiving a mean dose of 8.8 ± 10.6 of the same treatment.

Forty-seven patients (0.78%) died in the aspirin group and 45 patients (0.73%) died in the low-molecular-weight-heparin group. Additionally, 2.51% of patients experienced deep-vein thrombosis in the aspirin group while 1.71% of patients in the low-molecular-weight-heparin group experienced the same condition. Bleeding complications, pulmonary embolism, and other serious adverse events occurred at the same incidence rate in both groups

“In patients with extremity fractures that had been treated operatively or with any pelvic or acetabular fracture, thromboprophylaxis with aspirin was noninferior to low-molecular-weight heparin in preventing death and was associated with low incidences of deep-vein thrombosis and pulmonary embolism and low 90-day mortality,” the researchers concluded.

The authors of the study, which was funded by the Patient-Centered Outcomes Research Institute, highlighted several limitations including noting that patients were allowed to receive up to two doses of low-molecular-weight heparin prior to the start of the trial.



  1. O’Toole RV, Stein DM, O’Hara NN, et al. Aspirin or low-molecular-weight heparin for thromboprophylaxis after a fracture. N Engl J Med. 2023;388:203-213. doi:10.1056/NEJMoa2205973
  2. Aspirin as effective as blood thinner injections to prevent deadly complications in patients hospitalized with bone fractures. News release. Science Daily; January 18, 2023. Accessed February 2, 2023.