Venous Thromboembolism in Critically Ill Medical Patients Receiving Chemoprophylaxis: A Focus on Obesity and Other Risk Factors.

Purpose: To compare the incidence of 90-day venous thromboembolism (VTE) in obese critically ill medical patients receiving VTE chemoprophylaxis with nonobese patients of similar illness severity. We also identified other VTE risk factors.

Methods: Eligible patients spent ≥24 hours in an intensive care unit between November 2007 and November 2013 and received VTE chemoprophylaxis within 48 hours of admission. The primary outcome was 90-day VTE.

Results: A total of 11 111 patients were evaluated, of which 1732 obese and 1831 nonobese patients were enrolled with mean BMIs of 38.9 ± 9.2 kg/m(2) and 24.5 ± 3.1 kg/m(2) and mean Acute Physiology and Chronic Health Evaluation II scores of 28.4 ± 11.8 and 26.6 ± 11.7, respectively. The rate of 90-day VTE for the total cohort, obese, and nonobese patients was 6.5%, 7.5%, and 5.5%, respectively. Obese patients were more likely to develop VTE compared with nonobese patients (odds ratio [OR]: 1.41; 95% confidence interval [CI]: 1.03 -1.93). Other risk factors significantly associated with 90-day VTE included prior VTE (OR: 3.93; 95% CI: 1.83-8.48), trauma with surgery in the previous 30 days (OR: 3.70; 95% CI: 1.39-9.86), central venous catheters (OR: 2.64; 95% CI: 1.87-3.72), surgery within 90 days (OR: 2.40; 95% CI: 1.61-3.58), mechanical ventilation (OR: 1.94; 95% CI: 1.39-2.71), male sex (OR: 1.55; 95% CI: 1.13-2.14), and increasing age using 1-year increments (OR: 1.02; 95% CI: 1.01 -1.03).

Conclusions: The rate of VTE in critically ill medical patients remains high despite standard chemoprophylaxis. Obesity is among 8 risk factors independently associated with 90-day VTE.