Pulmonary Embolism Incidence Is Increasing with Use of Spiral Computed Tomography

Background Pulmonary embolism causes significant morbidity in hospitalized patients, yet few studies have explored the impact of spiral computed tomography (CT) scanning on diagnosis and clinical outcome. Methods Incidence rates of pulmonary embolism, chest and spiral CT rates, D-dimer assay, anticoagulation, and in-hospital mortality were assessed on statewide pulmonary embolism discharge data (1997-2001) from the Pennsylvania Health Care Cost Containment Council. Results The incidence of pulmonary embolism increased from 47 to 63 per 100,000 patients from 1997 to 2001 (mean of 0.004% per year, P< .001). Mean pulmonary embolism incidence rates were higher for African American patients (0.031% per year higher than for white patients), patients aged 70 years or more (0.007% higher than for patients aged < 70 years), and female patients (0.013% higher than for male patients) (all P < .001). Concomitantly, the proportion undergoing CT (including spiral) scans increased from 23.23% to 45.18% (odds ratio = 1.30; P < .001), controlling for age, gender, race, and cancer, whereas rates for other procedures remained unchanged. By comparing 1999 and before with 2000 and after, there was a significant decrease in the 2 highest Atlas Severity of Illness categories (49.4%-37.7%) and a significant increase in the 3 lowest categories (50.6%-62.3%; P<.001). The risk of in-hospital deaths among patients with pulmonary embolism decreased in this period from 12.8% to 11.1% (P<.001). Conclusion The incidence of pulmonary embolism is increasing with the increasing use of spiral CT scans, with a lower severity of illness and lower mortality, suggesting the increase is due to earlier diagnosis.