Microbiological Trends, in-hospital Outcomes, and Mortality in Infective Endocarditis: A Swiss Nationwide Cohort Study

Background. The epidemiology of infective endocarditis (IE) is evolving, driven by an aging population and increased use of endovascular devices, and is associated with significant morbidity and mortality. This study aims to evaluate changes in microbiological trends and clinical outcomes in patients with IE over the past decade in Switzerland. Methods. This nationwide cohort study analyzed in-hospital claims data from patients hospitalized with IE in Switzerland between 2012 and 2021. We assessed incidence rates per 100 000 hospitalizations, categorizing them by common pathogens. The outcomes included in-hospital and 6-month mortality, admission to the intensive care unit, and length of hospital stay. Results. Among 15 255 hospitalizations with IE, the annual number of cases increased from 1361 in 2012 to 1636 in 2021. The most frequently diagnosed pathogens were Staphylococcus aureus (increasing from 19.8% to 30.0%, P-trend < .01) and Streptococcus species (from 17.6% to 24.4%, P-trend < .01). Infective endocarditis caused by Staphylococcus aureus was associated with the highest in-hospital (19.9%) and 6-month mortality (30.3%), and intensive care unit admission rates (44.2%), with no relevant changes over time. The longest length of hospital stay was observed in hospitalizations with IE caused by Enterococcus species (mean 23.9 days) and S. aureus (23.8 days). Conclusions. This nationwide cohort study showed an increase in IE hospitalizations from 2012 to 2021, primarily from S. aureus and Streptococcus species. Predominantly, S. aureus was associated with adverse outcomes that remained consistently high over time compared to other or unidentified pathogens.