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

Abstract

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.