Secular trends in occurrence of acute venous thromboembolism: the Worcester venous thromboembolism study (1985 to 2009)

BACKGROUND: The clinical epidemiology of venous thromboembolism has changed recently due to advances in identification, prophylaxis, and treatment. We sought to describe secular trends in occurrence of venous thromboembolism among residents of the Worcester, Massachusetts, metropolitan statistical area (WMSA). METHODS: Population-based methods were used to monitor trends in event rates of first-time or recurrent venous thromboembolism in 5025 WMSA residents diagnosed with acute pulmonary embolism and/or lower-extremity deep vein thrombosis during 9 annual periods between 1985 and 2009. Medical records were reviewed by abstractors and validated by clinicians. RESULTS: Age- and sex-adjusted annual event rates for first-time venous thromboembolism increased from 73 (95% CI 64-82) per 100,000 in 1985/1986 to 133 (122-143) in 2009, due mostly to an increase in pulmonary embolism. The rate of recurrent venous thromboembolism decreased from 39 (32-45) in 1985/1986 to 19 (15-23) in 2003, and then increased to 35 (29-40) in 2009. There was an increasing trend in using non-invasive diagnostic testing, with about half of tests being invasive in 1985/1986 and almost all non-invasive by 2009. CONCLUSIONS: Despite advances in identification, prophylaxis, and treatment between 1985 and 2009, the annual event rate of venous thromboembolism has increased and remains high. While these increases may be partially due to increased sensitivity of diagnostic methods, especially for pulmonary embolism, it may also imply that current prevention and treatment strategies are less than optimal