Assessment of the Relationship between Body Mass Index and Incidence of Venous Thromboembolism in Hospitalized Overweight and Obese Patients

tudy Objective To assess whether a positive linear association exists between body mass index (BMI) and incidence of venous thromboembolism (VTE) in overweight and obese hospitalized patients. Design Single-center, retrospective, observational cohort study. Setting Large, academic, tertiary care medical center. Patients A total of 1452 adults hospitalized between January 1, 2013, and December 31, 2014, who weighed more than 100 kg and had a BMI of 25 kg/m2 or greater on admission, and received heparin subcutaneously for VTE prophylaxis; patients were categorized into four subgroups based on World Health Organization BMI classification: overweight (141 patients), obese class I (305 patients), obese class II (324 patients), and obese class III (682 patients). Measurements and Main Results The primary outcome was occurrence of VTE in each subgroup; all-cause mortality and length of hospital stay were secondary outcomes. A linear trend test did not show an association between occurrence of VTE and BMI ≥ 25 kg/m2. VTE occurred in 7(5%) of 141 patients in the overweight group, 5 (2%) of 305 in the obese class I group, 8(3%) of 324 in the class II group and 18 (3%) of 682 in the class III group (p=0.573). In addition, no linear association was noted between all-cause mortality or length of hospital stay and BMI ≥ 25 kg/m2. Overall mortality was 10% (146/1452 patients). Ten deaths (7%) occurred in the overweight group, 45 (15%) in the obese class I group, 38 (12%) in the obese class II group, and in 53(8%) the obese class III group (p=0.067). The median length of hospital stay was 5 (interquartile range 3-9) days (p=0.122) for all patients. Conclusion In overweight and obese hospitalized patients who weighed more than 100 kg and had a BMI of 25 kg/m2 or greater, the incidence of VTE did not increase incrementally with increasing severity of obesity. This article is protected by copyright. All rights reserved.