Epidemiological Analysis of Infective Endocarditis at the Gold Coast Area Health Service, Australia

Abstract

Introduction: Infective endocarditis is known to be a condition which is associated with high mortality and morbidity. Some studies indicate an in-hospital mortality of 16% with a one-year mortality of 37% with infective endocarditis. Aim: We aim to determine the risk factor profile, valve profile, complication rates, mortality, microorganisms involved and impact of antimicrobial resistance of patients with infective endocarditis at the Gold Coast area health service. Design: We performed a retrospective single-center analysis on 111 patients of 18 years old and above with echo-proven infective endocarditis who were followed at the department of cardiology, Gold coast area health service from January 2011 to December 2015. Place and Duration of Study: Department of Cardiology, Gold coast area health service, January 2011 to December 2015. Inclusion Criteria: Age > 18 years, index hospital stay with infective endocarditis, echocardiographic evidence of endocarditis. Results: Median age: 59 years, median length of stay: 21 days, male predominance (68% males, 32% females), mitral valve was the most commonly involved valve, surgical intervention in 20%, mortality 16%. Risk factors: Intravenous drug use was the most common risk factor (28%).Presence of prosthetic heart valve (mechanical and bioprosthetic) was the second most common risk factor. Other risk factors-healthcare related endocarditis (14%), previous episodes of endocarditis (15%), rheumatic heart disease and intracardiac device (8%). Methicillin-sensitive Staphylococcus aureus (MSSA) was the most commonly involved organism (46%) followed by streptococcus (26%), Enterococcus (11%). Methicillin-resistant Staphylococcus aureus (MRSA) was involved in 5% of the patients. Septic emboli was the most common complication (42%). Heart failure which complicated endocarditis in 38% of patients had a relative risk of mortality of 2.83 (p=0.018, 95% [CI] 1.1-6.7). Arrhythmias happened in 11% of patients which posed a relative risk of mortality, (RR- 2.71, p=0.037, 95% [CI] 1.0-6.9). The RR for mortality in the non-surgical group was 2.09 (RR-2.09, 95% [CI] 0.5-8.4, P= 0.3) compared to the surgical group. Conclusion: The key findings in our single center study were that intravenous drug use and health care related endocarditis were the most common reversible risk factors of endocarditis with complications of heart failure and arrhythmias posing a significant risk of mortality.