Evaluating Adequacy of VTE Prophylaxis Dosing with Enoxaparin for Overweight and Obese Patients on an Orthopedic-Medical Trauma Comanagement Service.

OBJECTIVES

Venous thromboembolism (VTE) is a common nosocomial condition, developing frequently in overweight and obese patients. VTE prophylaxis with weight-based enoxaparin dosing may be more effective than the standard dosing regimen for overweight and obese patients; however, weight-based dosing is not practiced routinely. In this pilot study we sought to evaluate prophylactic anticoagulation regimens used for VTE prevention in overweight and obese patients on the Orthopedic-Medical Trauma (OMT) service to inform the need for modification of dosing practices.

METHODS

This prospective, observational study evaluated the adequacy of current VTE prophylaxis practice at an academic tertiary center, including overweight and obese patients admitted during 2017-2018 to an OMT comanagement service. It included patients hospitalized for at least 3 days with a body mass index (BMI) of ≥25 and prescribed enoxaparin. Steady-state antifactor Xa trough and peak levels were monitored after three doses. Frequency of in prophylactic range (0.2-0.44) antifactor Xa levels and VTE events were compared by BMI groups and enoxaparin dosing using the χ2 test.

RESULTS

There were 404 inpatients included: 41.1% were overweight (BMI 25-29), 43.4% were obese (BMI 30-39), and 15.6% were morbidly obese (BMI ≥40). A total of 351 patients (86.9%) received standard dose enoxaparin 30 mg 2 times per day (BID), and 53 patients received enoxaparin 40 mg BID or more. A number of patients (213; 52.7%) did not achieve prophylactic range antifactor Xa levels. A significantly higher number of patients in the overweight group achieved prophylactic range antifactor Xa compared with obese and morbidly obese groups (58.4% vs 41.7% and 33%, P = 0.002 and 0.0007, respectively). Morbidly obese patients treated with enoxaparin 40 mg BID or higher versus enoxaparin 30 mg BID had fewer VTE events (4% vs 10.8%, P = 0.18).

CONCLUSIONS

The current practice of VTE enoxaparin prophylaxis may not be adequate for overweight and obese OMT patients. Further guidelines are needed to implement weight-based VTE prophylaxis in overweight and obese hospitalized patients.