Objectives: The aim of this study was to assess whether non-specific clinical signs or biological results can identify patients with a high probability of infective endocarditis (IE) to improve outcome.
Patients and methods: All patients tested for IE were included in a cohort and classified according to the modified Duke criteria. Patients with rejected endocarditis served as controls. Univariate and multivariate analyses were performed, and a score was calculated by adding 1 when a variable independently associated with IE (excluding major Duke criteria) was present and 0 when the variable was absent. A second score for patients with prior valvular damage (PVD) was also used. Scores were evaluated using the ROC curve method.
Results: IE was diagnosed in 402 of 2039 participants (19.7%). By multivariate analysis, PVD, fever, emboli, stroke, splenomegaly, finger clubbing, leucocytosis and erythrocyte sediment rate >50 were independently associated with IE. The rate of IE increased significantly from 4% (10/254) for a score of 0 to 83% (10/12) for a score of 6 in all patients, and from 9.5% (23/241) to 100% (10/10) in patients with PVD. The area under the ROC curve was 0.75 for the first score and 0.7 for the second. In a prospective study of 117 patients with suspicion of IE, the proportion of confirmed IE was 19% and the area under the ROC curve was 0.72.
Conclusions: This simple score can be used to identify patients with a high probability of IE, in the emergency room or on admission, to speed up diagnosis, or to initiate empirical antimicrobial therapy without replacing the modified Duke criteria.