Increasing Incidence and Declining Mortality After Cancer-Associated Venous Thromboembolism: A Nationwide Cohort Study

Purpose: The incidence of cancer-associated venous thromboembolism has increased, but whether short-term mortality after cancer-associated venous thromboembolism has changed remains uncertain. We investigated whether the increasing incidence of venous thromboembolism in cancer patients is associated with a change in mortality. Methods: We used administrative medical registries to identify a cohort of all Danish patients diagnosed with a first primary cancer from 2006 to 2017. We examined temporal changes in 1-year risks of venous thromboembolism and in mortality risks at 30 days and 1 year after venous thromboembolism. Cox regression was used to assess changes in mortality rate ratios over time. Results: We included 350,272 cancer patients (median age 68 years, 49.1% female), of whom 8167 developed venous thromboembolism within 1 year after cancer diagnosis. The cumulative 1-year risk of venous thromboembolism was 1.8% in 2006-2008, increasing to 2.8% for patients diagnosed in 2015-2017. The 30-day mortality after venous thromboembolism decreased from 15.1% in 2006-2008 to 12.7% in 2015-2017, and the 1-year mortality decreased from 52.4% to 45.8%, equivalent to a hazard ratio (HR) of 0.83 (95% confidence interval [CI], 0.75-0.90). This pattern of declining 1-year mortality was consistent for patients with pulmonary embolism, HR 0.79 (95% CI, 0.69-0.90), and deep venous thrombosis, HR 0.76 (95% CI, 0.67-0.87). Lower mortality over time was evident across all strata of cancer stage, cancer type, and cancer treatment. Conclusions: The 1-year risk of venous thromboembolism after a first primary cancer diagnosis in Denmark increased during 2006-2017. This increase was accompanied by declining mortality.