From structural heart lesions to host burden: changing epidemiology and outcomes of native valve infective endocarditis, a nationwide study, 2006-2023.

BACKGROUND: The epidemiology of native valve infective endocarditis (IE) has shifted toward older adults with substantial comorbidity burdens, yet contemporary nationwide data on outcomes and surgical impact remain limited. METHODS: We conducted an 18-year nationwide cohort study of adults hospitalised with native valve IE in Korea (2006-2023). Outcomes included in-hospital and 5-year all-cause mortality, IE relapse and a composite of death or relapse. Temporal trends, mortality predictors and surgical associations across age strata were evaluated using multivariable Cox models and stratified survival analyses. RESULTS: Among 18 402 patients (mean age 63.7 years), incidence declined in individuals <45 years but increased in those ≥65 years. In-hospital mortality was 25.5%, and 5-year mortality exceeded 50% overall. Advanced age, dialysis dependence, cancer and major complications predicted mortality. Valve surgery, performed in 29.1% of patients, was consistently associated with lower short- and long-term mortality across age groups, with no evidence of age-by-treatment interaction. Both early (≤7 days) and late (>7 days) surgery showed reduced mortality versus medical therapy. IE relapse was more frequent in older adults, and surgery was associated with a lower relapse risk. In the composite outcome of death or relapse, older adults had a higher event burden, whereas surgery remained associated with fewer composite events. CONCLUSIONS: Native valve IE in Korea has shifted toward an elderly, multimorbid population with persistently high mortality. Despite declining utilisation, the survival benefit of surgery was preserved across the age spectrum, supporting operative consideration in appropriately selected older adults.