**10. COPD**

Hospitalized patients with exacerbations of COPD, when routinely evaluated, showed PE in 25% to 29%.108,109From 1979 to 2003, 58,392,000 adults older than 20 years were hospitalized with COPD in short-stay hospitals in the United States.110 PE was diagnosed in 381,000 (0.65%) and DVT in 632,000 (1.08%).110 The relative risk for PE in adults hospitalized with COPD was 1.92 and for DVT it was 1.30. Among those aged 20 to 39 years with COPD, the relative risk for PE was 5.34. Among patients with COPD aged 40 to 59 years, the relative risk for PE decreased to 2.02, and among patients aged 60 to 79 years the relative risk for PE was 1.23.110 The relative risk for DVT was also higher in patients with COPD aged 20 to 39 years (relative risk 5 2.58) than in patients aged 40 years or older (relative risk 0.92-1.17, depending on age).110 In young adults, other risk factors in combination with COPD are uncommon, so the contribution of COPD to the risk of PE becomes more apparent than in older patients. Although these data strongly suggest that COPD is a risk factor for PE and DVT, multivariate logistic analysis did not identify it as an independent risk factor.43 Others, with univariate analysis, did not identify COPD as a risk factor.61

Neuhaus et al. 111 found pulmonary emboli in 27% of 66 autopsies performed in patients who had respiratory failure (not only as a decompensation of COPD) and died after admission to a Respiratory Intensive Care Unit.

The largest study was conducted by Schonhofer and Kohler 112 on a population of 196 patients admitted to a respiratory intensive care unit. The authors found a DVT rate of 10.7% as assessed by US. The majority (86%) of cases were asymptomatic and, interestingly, almost all major clinical variables (such as age, weight, severity of dyspnea, lung function, situation of blood gases) failed to predict patients who were more likely to develop DVT.
