Infective endocarditis in the real world: Diagnostic challenges and predictors of in-hospital mortality in a 10-year retrospective cohort from a Brazilian tertiary center.

Infective endocarditis (IE) remains a life-threatening condition with high mortality, particularly in middle-income countries where access to advanced diagnostics and timely surgery is unequal. Real-world data from such settings remain limited. This study describes the clinical and microbiological characteristics of patients with suspected IE and identifies independent predictors of in-hospital mortality at a Brazilian tertiary referral center. We conducted a retrospective cohort including adults hospitalized with suspected IE between 2012 and 2022. Cases were classified according to modified Duke criteria. Demographic, clinical, laboratory, microbiological, and echocardiographic data were collected, and independent predictors of in-hospital mortality were identified using multivariable logistic regression. Of the 112 patients evaluated, 66 met the criteria for definite or possible IE. Median age was 55 years, 59.1% were male, and 34.8% were ≥60 years. Structural heart disease was present in 87.8%, predominantly involving the mitral valve. Blood cultures were positive in 57.1%, with Staphylococcus aureus as the leading pathogen (25%), whereas 42.9% were culture-negative. Echocardiographic evidence of IE was documented in 80.9%, and valve surgery was performed in 51.5%. In-hospital mortality was 36.6%. Independent predictors of death included age ≥60 years (OR 7.0), hypertension (OR 3.9), new valvular regurgitation (OR 6.3), thrombocytopenia ≤150×10³/mm³ (OR 3.5), total bilirubin ≥1.2 mg/dL (OR 15.4), and arterial lactate >1.6 mmol/L (OR 5.2). In this real-world cohort, IE was characterized by diagnostic limitations, a high proportion of culture-negative cases, and high in-hospital mortality. Readily available clinical and laboratory parameters showed prognostic value and may support early risk stratification in resource-limited settings.