Health care exposure and age in infective endocarditis: results of a contemporary population-based profile of 1536 patients in Australia

Institutional-based studies of infective endocarditis (IE) are limited by referral bias. Longitudinal population-based data were used to overcome such bias to provide a contemporary profile of IE and specifically investigate the importance of health care-associated IE and age. Between 2000 and 2006, 1536 consecutive adult admissions with IE were identified in the Australian state of New South Wales using a state-wide database. The annual incidence was 4.7 per 100 000 (95% CI 4.4-4.9) being highest in patients aged between 80 and 84 years. The most frequent causative organism was Staphylococcus aureus (32%). Surgery was performed in 20% and the 6-month mortality was 18%. During the study period, the median age of patients increased from 61 to 65 years (P = 0.02), but microbiology, surgery, and mortality rates remained stable. Health care-associated IE was identified in 30% and was associated with older age, diabetes, renal impairment, heart failure, and infection with methicillin-resistant Staphylococcus aureus and enterococcus. Even after adjustment for these differences, recent health care exposure was an independent predictor of mortality (hazard ratio 1.62, 95% CI 1.34-1.96). Contemporary IE contributes to health care-related infection, occurs in an increasingly elderly population, and remains a condition with unacceptably high mortality.