Prognostic Value of Blood Urea Nitrogen for Short-Term Mortality in Patients with Infective Endocarditis

Blood urea nitrogen (BUN) is a metabolic product validated to be an independent risk factor in the prognosis of several diseases. However, the prognostic value of BUN in patients with infective endocarditis (IE) remains unevaluated.A total of 1371 patients with a diagnosis of IE were included and divided into four groups according to BUN (mmol/L) at admission: < 3.5 (n = 343), 3.5-4.8 (n = 343), 4.8-6.8 (n = 341), and ≥ 6.8 (n = 344). Restricted cubic spline was used to assess the association of BUN with in-hospital mortality. Multivariate analysis was performed to identify the independent risk factors for adverse outcomes.The in-hospital mortality reached 7.4%, while the 6-month mortality was 9.8%. The restricted cubic spline plot exhibited an approximately linear relationship between BUN and in-hospital mortality. Receiver operating characteristics curve analysis showed that the optimal cut-off of BUN for predicting in-hospital death was 6.8 mmol/L. Kaplan-Meier analysis showed that patients with BUN > 6.8 mmol/L had a higher 6-month mortality than other groups (log rank = 97.9, P < 0.001). Multivariate analysis indicated that BUN > 6.8 mmol/L was an independent predictor indicator for both in-hospital [adjusted odds ratio (aOR) = 2.365, 95% confidence interval (CI) 1.292-4.328, P = 0.005] and 6-month mortality [adjusted hazard ratio (aHR) = 2.171, 95% CI 1.355-3.479, P = 0.001].BUN is suitable for independently predicting short-term mortality in patients with IE.