Heparin dosing for venous thromboembolism prophylaxis in obese hospitalized patients: An observational study

Objective: To compare rates of VTE occurrence in obese versus non-obese hospitalized patients who received UFH 5000 units subcutaneously q8 h. Materials and methods: This was a retrospective cohort study conducted in an academic medical center in the United States. Consecutive adult patients who were hospitalized during a 1-year time frame (2015) receiving UFH 5000 units subcutaneously q8 h for VTE prophylaxis. The primary outcome was occurrence of VTE during hospitalization. This was compared between obese (body mass index >= 30 kg/m(2)) and non-obese (body mass index< 30 kg/m(2)) patients. Secondary outcomes included the occurrence of significant bleeding (i. e. intracranial and gastrointestinal hemorrhage). Results: There were 5110 patients included in the study cohort, with a mean age of 57 +/- 18 years; and 54% (n=2757) were male. A similar proportion of patients in the obese group (n=11/1673, 0.7%) and non-obese group (n=19/3437, 0.6%) developed a VTE (difference 0.1%, 95% CI -0.4 to 0.6%, p=0.70). The incidence of VTE was also low (n=1/394, 0.3%) in patients with body mass index >= 40 kg/m(2). Intracranial bleeding occurred in 3 (0.2%) patients in the obese group and 2 (0.1%) patients in the non-obese group (difference 0.1%, 95% CI -0.1 to 0.3%, p=0.34). Gastrointestinal bleeding occurred in 6 (0.4%) patients in the obese group and 13 (0.4%) patients in the non-obese group (difference 0%, 95% CI -0.4 to 0.3%, p > 0.99). Conclusions: UFH 5000 units subcutaneously q8 h may be sufficient for prevention of VTE in obese patients.