Introduction. Infective endocarditis (IE) is a potentially life-threatening disease with a worldwide increasing incidence. Despite recent improvements in diagnosis and treatment, IE remains associated with high morbidity and mortality and additionally burdens healthcare systems with high treatment and consequential costs. However, data from population-based studies in IE are scarce. In the present study, we aimed to investigate (1) incidence; (2) patient characteristics; (3) trends in pathogen presentation; and (4) in-hospital mortality of all IE cases in a large, nationwide German registry.  

Methods and Results. We analyzed healthcare records of all IE cases >18 years from 2007 to 2019 obtained from the German Federal Bureau of Statistics. In total, 86,469 cases were hospitalized due to IE during this period. The mean age was 66 years and 31.8% (n = 27,534) were female. Cardiovascular comorbidities such as hypertension (44.8%, n = 38,792), diabetes (27.2%, n = 23,556), atrial fibrillation (38.1%, n = 32,955), and chronic obstructive pulmonary disease (COPD; 8.7%, n = 7,576) were common. Within the total cohort, streptococcus (26.4%, n = 22,863), staphylococcus (24.5%, n = 21,241), gram-negative (including the HACEK group) (12.7%, n = 10,996), andescherichia coli (9.3%, n = 1,733) were the most commonly identified organisms. The proportion of staphylococcus gradually increased over time (20.7% in 2007 to 2010; 23.8% in 2011 to 2013; 25.9% in 2014 to 2016; 26.9% in 2017 to 2019), whereas rates of negative blood cultures decreased over time. Compared to patients with negative blood cultures, those with staphylococcus and gram-negative (including the HACEK group) were associated with higher risk of in-hospital mortality (odds ratio [OR] 1.31, 95% confidence interval [CI] 1.25-1.37); OR 1.33, 95%-CI 1.26-1.41, respectively). Factors associated with higher likelihood of in-hospital mortality were advanced age, female sex, higher comorbidity burden (e.g., heart failure, COPD, and stroke), acute renal failure, acute myocardial infarction, need for dialysis or invasive ventilation, and concomitant sepsis. The overall in-hospital mortality in patients with IE was 14.8% and in-hospital mortality rates increased over time (13.4% in 2007 to 2010; 14.2% in 2011 to 2013; 14.8% in 2014 to 2016; 16.5% in 2017 to 2019). 

Conclusions. In this nationwide cohort, streptococcus and staphylococcus were the most common pathogens. We observed a shift in bacterial patterns with a gradual increase in the incidence of staphylococcus over time. Bacteremia with staphylococcus and gram-negative (including the HACEK group) was associated with a higher likelihood of in-hospital mortality in the setting of IE. Patients hospitalized for IE showed high overall in-hospital mortality rates which gradually increased over time. Our results highlight the need for new interventions and preventive strategies with carefully selected antibiotic therapy in patients with IE.