Pulmonary Embolism in Cancer Patients Is Associated with Lower Severity of Illness and Lower Mortality Rates with Increasing Use of CT Scans.

Pulmonary embolism (PE) is a major cause of morbidity and mortality in patients with cancer (CA). However, predicting which CA patients will develop PE is not possible and thromboprophylaxis is infrequently used. In order to define the incidence and clinical characteristics of CA patients with PE, we analyzed discharge data from all patients with PE collected by the Pennsylvania Health Care Cost Containment Council (PHC4) from 1997–2001. The analyses included all PE discharges with ICD-9 codes 415.11 and 415.19, excluding pregnant patients and all second or later PE admissions. Cancer diagnoses were enumerated by ICD-9 codes 140–239 and diagnostic procedures by revenue codes for computerized tomographic (CT) (including spiral CT) scans. Of 33,036 PE patients identified in this period, one-quarter had cancer, among whom PE incidence increased marginally, from 1,589 (24.0%) in 1997 to 2,262 (25.4%) in 2001, p = 0.072. CA patients were more likely to be Caucasian, OR 1.22, p<0.001, greater than 70 years of age, OR 1.16, p<0.001, and male, OR 1.19, p<0.001. CA of the lung was the most common CA type associated with PE, 1150 (17.7%), followed by CA of the digestive tract, 1150 (17.4%); genitourinary tract, 832 (12.6%); and lymphatic/hematopoetic tissues, 771 (11.7%). CT scans were performed with increasing frequency in CA PE patients, from 27.7% in 1997 to 50.0% in 2001, p < 0.001, and more frequently in Caucasians than in blacks, OR =1.61, p<0.001, and in those 70 years or younger, OR =1.91, p<0.001. At the same time, MediQual Atlas severity of illness scores decreased over time, from a mean 2.6 in 1997 to 2.3 in 2001, p<0.001, with a significant decrease in the two higher categories, 65.8% vs. 38.1%, and an increase in the three lowest categories, 34.2% to 61.9%, p<0.001. CA patients were less likely than non-CA patients to have other risk factors for PE, i.e. trauma, 3.7% vs. 8.1%, p< 0.001, or congestive heart failure, 12.9% vs. 20.8%, p<0.001. Although CA patients had higher mortality rates than non-CA PE patients, OR 1.86, p<0.001, these rates decreased from 23.3% in 1997 to 18.6% in 2001, p<0.001. In conclusion, patients with cancer account for one fourth of all PE, and they are typically elderly Caucasian males with cancer of the lung or digestive tract. The increasing use of CT scans in this group is associated with lower severity of illness scores and decreasing mortality rates, which suggest PE may be diagnosed earlier. Consideration of early thromboprophylaxis among CA patients at risk for PE may improve health outcomes.