Efficacy and safety of high-dose subcutaneous unfractionated heparin prophylaxis for the prevention of venous thromboembolism in obese hospitalized patients

Background: Obese patients experience a higher risk of venous thromboembolism (VTE) than their nonobese counterparts, which may warrant a more aggressive approach to thromboprophylaxis in this population. Objective: The purpose of this study was to compare rates of nosocomial VTE in obese patients treated with high-dose versus conventional-dose subcutaneous unfractionated heparin sodium (UFH) for thromboprophylaxis. Methods: A retrospective, single-center, cohort study was conducted to evaluate obese, adult, hospitalized patients admitted between April 2011 and April 2014 who received heparin 5,000 or 7,500 units subcutaneously every 8 hours for thromboprophylaxis. The primary outcome assessed the rate of nosocomial VTE in obese patients treated with high-dose heparin (7,500 units subcutaneously q 8 h) versus conventional-dose heparin (5,000 units subcutaneously q 8 h). Additionally, a secondary outcome assessed safety by quantifying bleeding events. Results: Nosocomial VTE occurred in 2/196 (1.02%) patients who received high-dose heparin thromboprophylaxis and in 5/2,182 (0.23%) patients who received conventional-dose heparin (p = .05). Bleeding occurred in 0/196 (0%) patients in the high-dose heparin group and in 2/2,182 (0.09%) patients in the conventional-dose heparin group (p = .67). All bleeding events were minor. Conclusions: This study failed to demonstrate a statistically significant reduction in the rate of nosocomial VTE in obese patients who received high-dose heparin thromboprophylaxis. Despite receiving a higher heparin dose, no increased risk of bleeding was observed in the high-dose group. Further investigation is needed to identify the optimal heparin dose for thromboprophylaxis in obese patients.