Contemporary Clinical Spectrum and Factors Associated with Mortality in Infective Endocarditis: A Multicenter Cohort Study (COSMO-IE).

Background

Despite continuous advancements in diagnostic imaging and targeted antimicrobial protocols for infective endocarditis (IE), global epidemiological data show that both disease burden and incidence continue to rise. This study aimed to evaluate real-world diagnostic and treatment approaches in accordance with the 2023 European Society of Cardiology (ESC) IE Guidelines and to identify independent predictors of mortality in a contemporary patient cohort.

Methods

This multicenter, retrospective cohort study analyzed data from 470 consecutive adult patients diagnosed with IE across 27 academic reference centers between 1 September 2023 and 1 June 2025. Patients were managed and adjudicated according to the 2023 ESC diagnostic criteria. Demographic data, clinical characteristics, microbiological profiles, imaging findings, empirical antibiotic therapy patterns, and clinical outcomes were analyzed. Independent predictors of mortality were determined using multivariable Cox proportional hazards regression models.

Results

The mean age of the overall study population was 58.08 ± 16.81 years, with a male predominance (60.6%, n = 285). Staphylococcus aureus was the most frequently isolated pathogen (27.9%), with a high proportion of methicillin resistance (38.9%). Hospital-acquired IE was identified in 41.1% of cases. Surgical treatment was performed in 40.6% (n = 191) of the cohort. The 28-day mortality rate was 11.9%, and the overall mortality during follow-up reached 26.4%. Multivariable Cox regression analysis identified hospital-acquired IE (HR = 2.247; 95% CI: 1.216-4.167; p = 0.010) and the presence of major clinical complications (HR = 4.207; 95% CI: 1.556-11.378; p = 0.005) as the strongest independent predictors of mortality.

Conclusions

Contemporary infective endocarditis is a highly complex and fatal disease characterized by a prominent healthcare-associated burden and a predominant staphylococcal etiology. The occurrence of major clinical complications and hospital-acquired infections were the primary independent predictors of mortality.