Time trends in all-cause mortality after first-time pulmonary embolism in adults aged 18 to 49 years in Sweden from 2006 to 2023: a nationwide registry–based study

BACKGROUND: Pulmonary embolism (PE) carries substantial mortality, but recent mortality trends and underlying causes of death among young adults during the last 2 decades remain insufficiently studied. OBJECTIVES: This study investigated time trends in all-cause mortality within 30 days, 31 to 365 days, and 1 to 3 years among patients with PE aged 18 to 49 years. Secondary aims included examining mortality trends in subgroups and cause-specific mortality. METHODS: This is a nationwide Swedish register study of patients aged 18 to 49 years with first-time PE, from 2006 to 2023. Mortality rates and temporal trends with age- and sex-adjusted rate ratios (aRRs) per 3-year interval were calculated using Poisson regression, overall and stratified by cancer, sex, age group, and pregnancy- and postpartum-related PE. RESULTS: Among 18 173 patients, 30-day mortality declined from 416.6 per 1000 person-years in 2006-2008 to 262.4 in 2021-2023 (aRR, 0.89; 95% CI, 0.84-0.94) but plateaued from 2015 to 2017. Mortality at 31 to 365 days (58.6-44.7 per 1000 person-years) and 1 to 3 years (14.7-14.2) remained stable over time. Among 1-year survivors, mortality declined among cancer patients (aRR, 0.84; 95% CI, 0.76-0.92). Venous thromboembolism was the leading cause of 30-day mortality among cancer-free patients. After 30 days, cancer was the leading cause of death, including among individuals without cancer at baseline. CONCLUSION: The 30-day mortality rate after first-time PE declined early in the study period, but plateaued from the period 2015-2017 onward. Mortality beyond 30 days remained stable and was only marginally attributable to venous thromboembolism as underlying cause, underscoring the importance of comorbidity management in postacute PE care.