Safety and efficacy of high-dose unfractionated heparin versus high-dose enoxaparin for venous thromboembolism prevention in morbidly obese hospitalized patients.

Venous thromboembolism is a cause of morbidity and mortality in hospitalized patients, and morbid obesity increases this risk. Various prophylaxis dosing strategies have been investigated. However, it is unclear if high-fixed dose enoxaparin or high-fixed dose unfractionated heparin thromboprophylaxis is optimal for minimizing the incidence of major bleeding and reducing hospital-acquired venous thromboembolism.

A single-center retrospective observational study was conducted in morbidly obese (body mass index ≥ 40 kg/m²) hospitalized patients who received either high-fixed dose enoxaparin (40 mg every 12 hours) or unfractionated heparin (7,500 units every 8 hours) for venous thromboembolism prophylaxis. Co-primary outcomes included incidence of major bleeding and venous thromboembolism diagnosed during hospitalization. Predictors of major bleeding were evaluated by multivariable regression.

In the 305 patients included (n=190 unfractionated heparin, n=115 enoxaparin), the incidence of major bleeding was significantly higher in the unfractionated heparin group (OR 1.85, 95% CI 1.07-3.13; p=0.025), with no significant difference in the incidence of venous thromboembolism diagnosed during hospitalization. The only independent predictors of major bleeding were intensive care acuity (OR 3.32, 95% CI 1.91-5.78; p<0.001) and selection of unfractionated heparin rather than enoxaparin for venous thromboembolism prophylaxis (OR 2.16, 95% CI 1.22-3.82; p=0.008).High-fixed dose unfractionated heparin for venous thromboembolism prophylaxis may lead to a higher risk of major bleeding events in morbidly obese patients compared to high-fixed dose enoxaparin.