The Rates of Bleeding and Venous Thromboembolism with Reduced-Dose Enoxaparin for Thromboprophylaxis in Low-Weight Surgical Patients: A Retrospective Cohort Study.

BACKGROUND

Low body weight is a recognized risk factor for bleeding with standard enoxaparin thromboprophylaxis (40 mg daily). Although reduced enoxaparin doses are used for venous thromboembolism (VTE) prevention in low-weight patients, data on bleeding and VTE outcomes remain limited.

OBJECTIVE

To evaluate rates of bleeding and VTE with the use of fixed dose of enoxaparin 30 mg daily in low-weight surgical patients.‎

Methods

A retrospective, single-center cohort study included low-weight surgical patients who received enoxaparin 30 mg daily from January 2018 to March 2024. The primary outcome was major ‎bleeding within 30 days postoperatively. Secondary outcomes included rates of overall bleeding ‎‎(major plus clinically relevant nonmajor bleeding) within 30 days and VTE events within 90 days. Risk factors were examined using logistic regression analysis or χ2 tests.

RESULTS

Data from 129 patients were analyzed. Six (4.7%) patients experienced major bleeding without fatality or bleeding at a critical anatomic site. The overall bleeding rate was 17.1% (n = 22). Five (3.8%) patients developed a VTE, including 2 pulmonary embolism events. Decreasing body weight (odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.81-0.97, P = 0.01), lower preoperative hemoglobin (OR = 0.97, 95% CI = 0.97-0.99, P = 0.04), and longer surgery durations (OR = 1.2, 95% CI = 1.05-1.40, P = 0.007) were independently associated with an increased risk of developing a bleeding event.

CONCLUSION AND RELEVANCE: In low-weight surgical patients, thromboprophylaxis with a reduced fixed dose of enoxaparin (30 mg daily) appears safe, with a major bleeding rate below 5%, comparable with rates observed with standard dosing thromboprophylaxis in landmark trials of surgical patients. Among low-weight patients, the lower body weight, preoperative anemia, and prolonged surgical duration were independently associated with increased bleeding risk. These findings highlight the importance of individualized risk assessment when considering a reduced fixed dose of enoxaparin for VTE prevention in low-weight patients undergoing surgery.