Obesity and pulmonary embolism: The mounting evidence of risk and the mortality paradox

Purpose: To determine the prevalence of pulmonary embolism in obese patients according to age, gender and comorbid conditions and explore the relation of obesity to mortality. Methods: The number of patients discharged from short-stay hospitals throughout the United States from 1998-2008 with pulmonary embolism who were obese or not obese, and in-hospital all-cause mortality were determined from the Nationwide Inpatient Sample. Results: From 1998-2008, 203,500 of 17,979,200 (1.1%) obese patients were diagnosed with pulmonary embolism compared with 2,034,100 of 346,049,800 (0.6%) non-obese patients [relative risk (RR) = 2.03]. Relative risk for pulmonary embolism was highest among obese patients aged 11-20 years (RR=5.80) and was higher in obese women (RR=2.08) than in obese men (RR=1.74). Mortality was 4.3% in obese patients with pulmonary embolism compared with 9.5% in non-obese patients (RR=0.45). Obesity had the greatest effect on mortality in older patients and little effect in teenagers and young adults. Among stable patients who did not receive thrombolytic therapy, mortality was 3.8% in obese patients and 8.4% in non-obese patients (RR=0.45). Among unstable patients, obesity had little effect on mortality. Conclusions: The prevalence of pulmonary embolism in hospitalized patients was higher in obese patients than in non-obese patients. Mortality in patients with pulmonary embolism was lower in obese patients than in non-obese patients, with the greatest effects in women, older patients and stable patients. (C) 2011 Elsevier Ltd. All rights reserved.