Evaluation of a Treatment-Dose Enoxaparin Protocol for Patients With Obesity

Background: Treatment-dose enoxaparin is not well studied in obese patients. Guidelines suggest that obese patients receiving enoxaparin therapy for acute venous thromboembolism (VTE) should receive a standard initial dose, 1 mg/kg, based on actual body weight. It is possible that this dosing strategy in obese patients may be overestimated, leading to a higher bleeding risk compared to non-obese patients. Objective: To gather data regarding enoxaparin treatment dosing and anti-Xa level monitoring in patients who are obese to guide dose adjustments. Methods: A single-center, retrospective chart review that included patients who were ordered treatment-dose enoxaparin and had a BMI >= 40 kg/m(2), which resulted in an automatic pharmacy consult.The primary endpoint of this study was incidence of bleeding. Results: The analysis included 102 patients. Most patients (92.1%) had a BMI of >= 40-60 kg/m(2) while 7.8% of patients had a BMI of > 60 kg/m(2). The average initial and final doses were 1.0 +/- 0.1 mg/kg and 0.9 +/- 0.2 mg/kg, respectively. The incidence of bleeding was 4.9%. The average dose for those that bled was 0.7 +/- 0.1 mg/kg. On average, patients who bled had higher BMIs than patients who did not bleed (51.6 kg/m(2) vs. 48.0 kg/m(2)). Of the 71 patients with an initial anti-Xa level, 42 of the levels were considered supratherapeutic (59.2%). Conclusion: A 1 mg/kg starting dose of enoxaparin may be too high for patients who are obese as many patients required an adjustment to their dose after initial anti-Xa levels.