Safety and Effectiveness of Reduced Dose Versus Standard Dose Enoxaparin Venous Thromboembolism Prophylaxis in Underweight Medically Ill Patients

Background: Enoxaparin is commonly used for venous thromboembolism (VTE) prophylaxis in hospitalized patients. Published literature exists for dose adjustment in higher body weights and renal dysfunction, but sparse literature on optimal dosing of prophylactic enoxaparin in underweight patients exists. Objective: To determine if there is a difference in adverse outcomes or effectiveness if enoxaparin VTE prophylaxis dosing is reduced to 30 mg subcutaneously once daily from standard dosing in underweight medically ill patients. Methods: This study was a retrospective chart review of a total of 171 patients, with 190 individual courses of enoxaparin included. Patients were ≥18 years of age, weighed ≤50 kg, and were given at least 2 days of consecutive therapy. Patients were excluded if they were taking anticoagulation upon admission, had a creatinine clearance <30 mL/min, were admitted to the ICU or a trauma or surgical service, or presented with bleeding or thrombosis. The Padua score and a modified score from the IMPROVE trial were used to evaluate baseline thrombotic risk and bleeding risk, respectively. Bleeding events were classified using the Bleeding Academic Research Consortium criteria. Results: No difference was seen in baseline risk of bleeding or thrombosis when comparing the reduced and standard dosing groups. No differences were observed with rates of bleeding, thrombotic events, mortality, or 30-day readmission. Conclusion: Both reduced and standard dosing strategies appeared effective for VTE prophylaxis, but neither showed superiority in reducing bleeding events. Additional larger studies are needed to evaluate safety and effectiveness of reduced dose of enoxaparin in this patient population.