Usefulness of neutrophil-to-lymphocyte ratio to predict in-hospital outcomes in infective endocarditis.

Background: The neutrophil-to-lymphocyte ratio is an independent predictor of worse prognosis in both infectious and cardiovascular disease. We hypothesized that an increased neutrophil-to-lymphocyte ratio at admission would predict in-hospital unfavourable outcomes in patients with infective endocarditis (IE).

Methods: We retrospectively analyzed clinical, laboratory, and echocardiographic data in a total of 121 consecutive adult patients (64 men; mean age, 54.7 ± 14.2 years) with definite IE.

Results: Among all patients, the prespecified clinical outcomes were experienced in 46 patients (38%). In-hospital mortality and central nervous system (CNS) events occurred in 29 (24%) and 21 patients (17%), respectively. The neutrophil-to-lymphocyte ratio at admission was found to be significantly higher for either composite end point. On using multiple Cox regression analysis, vegetation size ≥ 10 mm, end-stage renal disease, Staphylococcus aureus infection, low hemoglobin level, increased C-reactive protein (CRP) level, and high neutrophil-to-lymphocyte ratio at admission emerged as independent predictors of in-hospital unfavourable outcomes. In the receiver operating characteristics (ROC) curve analysis, a neutrophil-to-lymphocyte ratio > 7.1 had 80% sensitivity and 83% specificity in predicting adverse outcomes.

Conclusion: High neutrophil-to-lymphocyte ratio at admission is an independent predictor of in-hospital mortality and CNS events in patients with IE. However, prospective validation of these findings is required.