Trends in the Incidence of Deep Vein Thrombosis and Pulmonary Embolism: A 35-Year Population-Based Study.

Background: Recent trends in the incidence of venous thromboembolism (VTE), including idiopathic vs. non-idiopathic VTE, have not been well described.

Objective: To estimate the incidence of deep vein thrombosis (DVT) and pulmonary embolism with or without DVT (PE), and describe trends in incidence.

Methods: Using the resources of the Rochester Epidemiology Project, we identified all Olmsted County, MN residents with an incident DVT and PE over the 35-year period, 1966–2000 (n=3342). For all cases, the complete medical records in the community were reviewed for demographic and baseline characteristics previously identified as risk factors for VTE. Generalized linear models assuming a Poisson error structure, and using a log link function, and a log (population) offset will be used to assess the relationship of crude incidence rates to gender, year of diagnosis and age at diagnosis.

Results: The overall average age- and sex-adjusted annual VTE incidence was 122 per 100,000 person-years (DVT, 56 per 100,000; PE, 66 per 100,000), with higher age-adjusted rates among men than women (134 versus 115 per 100,000, respectively). VTE incidence rates increased exponentially with age for both genders, ranging from 4 to 1110 per 100,000 for age groups 0–19 to 90–110 years. Compared to the 5-year period, 1981–85 (when non-invasive diagnostic testing became routinely available), the overall VTE incidence through 2000 remains unchanged. However, the DVT incidence and the PE incidence significantly increased and decreased, respectively, adjusting for age and gender (p<0.001 for both). The overall age- and sex-adjusted annual incidence of idiopathic VTE was 11.7 per 100,000 person-years (DVT, 6.6 per 100,000; PE, 5.1 per 100,000), with age-adjusted rates also higher among men than women (15.1 vs. 9.1 per 100,000). Interestingly, again compared to 1981–85, idiopathic VTE incidence decreased for 1991–95 (p=0.001) and 1996–2000 (p=0.32), adjusting for age and gender. Idiopathic DVT incidence decreased for 1991–95 (p=0.09), and idiopathic PE incidence decreased for both 1991–95 (p=0.004) and 1996–2000 (p=0.03). The overall age- and sex-adjusted annual incidence of non-idiopathic VTE was 109.4 per 100,000 (DVT, 48.4 per 100,000; PE, 60.7 per 100,000), again, with age-adjusted rates higher in men than women (115.1 vs. 106.8 per 100,000). Non-idiopathic DVT incidence increased steadily since 1981–85 (p=0.006, p<0.001, and p<0.001 for increasing DVT incidence for 1986–1990–1991–1995–1996–2000, respectively, adjusting for age and gender). Non-idiopathic PE incidence, however, remained unchanged for 1986–2000.

Conclusions: VTE remains a major national health problem, especially among the elderly. Despite improved VTE prophylaxis efficacy and utilization, the overall incidence of VTE remains unchanged. However, the decreasing incidence of idiopathic DVT, and particularly idiopathic PE (with its associated poor survival) raises the possibility that the total number of VTE(PE)-related deaths may also be decreasing, albeit slightly. This hypothesis requires formal testing. The increasing or steady incidence of non-idiopathic DVT and PE, respectively, suggests the need for more widespread, effective VTE prophylaxis.