Community-acquired culture-negative endocarditis: clinical characteristics and risk factors for mortality

Summary Objectives We studied the clinical characteristics, in-hospital mortality, and long-term prognosis of patients with culture-negative endocarditis. Methods In total, 221 episodes of definite endocarditis were studied (2004–2009). We compared the clinical, laboratory, and echocardiography characteristics and the survival rates of patients with culture-negative and culture-positive endocarditis. Survival after hospital discharge was evaluated using the Kaplan–Meier method and coefficient of mortality comparisons. Results Culture-negative endocarditis occurred in 51/221 (23.1%) episodes. Compared with the culture-positive endocarditis patients, the time elapsed between admission and initiation of antibiotic therapy was longer in patients with culture-negative endocarditis ( p < 0.001), and these patients also had lower C-reactive protein levels at admission ( p < 0.001). In-hospital mortality rates were not different between culture-negative and culture-positive patients. After hospital discharge, there was also no significant difference between groups in survival curves ( p = 0.471). Severe sepsis (adjusted prevalence ratio 3.32, p = 0.010) and diabetes mellitus (adjusted prevalence ratio 2.32, p = 0.009) were independently associated with in-hospital death in culture-negative patients. Conclusions Culture-negative endocarditis patients presented with lower levels of C-reactive protein at admission and required more time for initiation of antibiotic therapy, although there was no difference in in-hospital mortality or long-term survival between culture-negative and culture-positive endocarditis patients. Diabetes mellitus and severe sepsis were associated with in-hospital death in patients with culture-negative endocarditis.