Clinical Characteristics, Microbiology, and In-Hospital Outcomes of Infective Endocarditis at a Tertiary Cardiac Center in Saudi Arabia: A Retrospective Cohort Study

Background: Infective endocarditis (IE) carries high morbidity and mortality, and its epidemiology in Saudi Arabia reflects a transition in which rheumatic and prosthetic valve disease coexist. Contemporary single-center data describing the clinical profile, microbiology, and in-hospital outcomes of IE in this setting remain limited. Methods: We conducted a retrospective cohort study at a tertiary cardiac center in Riyadh, Saudi Arabia, including 102 patients with IE diagnosed between October 2020 and December 2024, classified using the modified Duke criteria. Variables were analyzed descriptively. Proportions are reported with 95% confidence intervals (CI; Wilson method) against the number of patients with available data, and missing data are reported as an explicit category. The study is reported in accordance with the STROBE statement. Results: The mean age was 46.7 ± 19.2 years (median 48, IQR 34-62), and 56 patients (54.9%, 95% CI 45.2-64.2) were male. The cardiac substrate was heterogeneous: rheumatic heart disease 32.4% (95% CI 24.1-41.9), prosthetic valve disease 30.4% (95% CI 22.3-39.9), degenerative valve disease 18.6% (95% CI 12.3-27.3), and congenital heart disease 14.7% (95% CI 9.1-22.9). Blood cultures were documented in 92 patients, with positivity in 52 (56.5%, 95% CI 46.3-66.2) and a culture-negative rate of 43.5% (95% CI 33.8-53.7). All-cause in-hospital mortality was 24.5% (24/98; 95% CI 17.0-33.9). ICU admission was required in 56.3% (49/87; 95% CI 45.9-66.3) and cardiac surgery in 38.0% (30/79; 95% CI 28.1-49.0). Conclusion: IE at this center presents across a heterogeneous cardiac substrate with substantial in-hospital mortality. A high culture-negative rate and considerable missingness in this retrospective dataset limit precision; findings should be regarded as descriptive and hypothesis-generating. Prospective, protocolized data with systematic long-term follow-up are needed.