Title: Evaluation of therapeutic enoxaparin dosing strategies in hospitalized patients with morbid obesity
Authors: Huelena Nguyen, PharmD; Nina Jacob, PharmD, BCPS; Priya Shah, PharmD, BCPS; Jessica Roth, PharmD, BCPS, CDCES; Shannan Shelton, PharmD, BCACP
Objective: Identify differences in bleeding outcomes between standard (1-1.5 mg/kg) and reduced (<1 mg/kg) therapeutic enoxaparin dosing in patients with morbid obesity
Self Assessment Question: Which of the following statements is true regarding therapeutic enoxaparin dosing in patients with morbid obesity?
- Reduced dosing is consistently recommended due to increased bleeding risk
- Standard dosing may still be appropriate despite concerns for bleeding
- Anti Xa monitoring has no utility in obesity
- Dosing is similar in patients with obesity compared to patients of normal weight
Background: The objective of this study is to compare bleeding outcomes between standard and reduced dosing strategies in hospitalized adults with morbid obesity treated for venous thromboembolism
Methods: This multicenter, retrospective, observational case-cohort study evaluated adult inpatients ordered enoxaparin from the therapeutic enoxaparin dosing order set between July 1, 2023 to June 30, 2025 at ChristianaCare hospitals. Patients were included if they were at least 18 years old and had a body mass index (BMI) ≧40 kg/m2 or weight ≧150 kg and received at least 24 hours of therapy, while patients with a creatinine clearance <30 mL/min, intensive care unit admission, pregnancy or postpartum, recent trauma, known bleeding disorders, thrombocytopenia, cirrhosis, or history of heparin induced thrombocytopenia were excluded. Data collected included weight, enoxaparin dose, indication, concomitant medications, anti-Xa levels, and clinical outcomes, including major bleeding, minor bleeding, and thrombotic events. Descriptive statistics were used to evaluate baseline characteristics and categorical outcomes were compared using chi-square tests.
Results: A total of 1566 patients were screened, and 116 patients met inclusion criteria. The primary outcome is the proportion of major bleeding events during therapy and within 24 hours of discontinuation. Four major bleeding events (3.96%) occurred in the standard dose group compared to one event (6.67%) in the reduced dose group (p=0.506). Secondary outcomes include the proportion of minor bleeding events, therapeutic anti-Xa levels, and characterization of reduced dosing in patients with morbid obesity. Three minor bleeding events (2.87%) occurred in the standard dose group, and three events (20%) occurred in the reduced dose group (p=0.028). There was an inability to determine statistically significant differences for the remaining outcomes.
Conclusion: These findings suggest that there may be a difference in bleeding events between standard and reduced dosing strategies. The results of this study will provide insight into prescribing patterns of therapeutic enoxaparin in patients with morbid obesity and evaluate the safety of reduced dosing strategies. This will help support optimization of treatment guidelines in this high-risk population, but still highlights the need for ongoing evaluation in patients with BMI ≥40 kg/m².
