Clinical significance of the controlling nutritional status (CONUT) score in patients with infective endocarditis

Risk stratification of patients with infective endocarditis (IE) is difficult. The Controlling Nutritional Status (CONUT) score is an index of immune function and nutritional status. We investigated the prognostic value of the CONUT score in IE and whether its prognostic value differed between IE patients with and without indications for surgery. Clinical records were retrospectively evaluated for 92 patients with IE treated at Nihon University Itabashi Hospital and Nihon University Hospital between January 2014 and May 2019. The CONUT score was determined upon admission, and patients were divided into two groups at the median score (≤7 [n = 50] and ≤8 [n = 42]). The primary outcome was all-cause mortality at 90 days after admission. The high CONUT group had significantly higher C-reactive protein and N-terminal pro-brain natriuretic peptide levels, as well as a significantly lower hemoglobin and estimated glomerular filtration rate (all P < 0.05), and considerably more valve perforation (26% versus 8%, P < 0.05). Kaplan-Meier analysis revealed that mortality was significantly higher in the high CONUT group (P < 0.001). Even after adjusting for the propensity score based on IE risk factors, a higher CONUT score was still associated with mortality. A receiveroperating characteristic analysis revealed that a CONUT score ≤8 had a sensitivity of 86% and specificity of 76% for predicting all-cause mortality. A CONUT score ≤8 was most strongly associated with mortality in patients with surgical indications (P < 0.001). In patients with IE, a higher CONUT score was significantly associated with inflammation, heart failure, renal dysfunction, anemia, valve dysfunction, and short-term mortality, especially in patients with surgical indications.