Low Prognostic Nutritional Index Contributes to High Risk of Adverse Events in Patients Undergoing Surgical Valve Replacement

Abstract

Background Prognostic nutritional index (PNI) score is a useful indicator to evaluate the nutritional status of patients. However, the nutritional significance of the PNI score and its ability to predict clinical prognosis in patients with surgical valve replacement (SVR) are unknown. The goal of this study was to analyze the association between PNI on admission and adverse events in patients following SVR.Methods This study included 485 patients who underwent successful SVR. Baseline PNI score was calculated before SVR on admission. The patients were divided into high and low PNI groups according to the cut-off value of PNI using the receiver operating characteristic (ROC) curve. Primary outcomes were composite adverse events, defined as worsening heart failure, myocardial infarction, major bleeding, uncontrolled infection, second surgery, post-operative arrhythmia or all-cause death during the follow-up. The association of PNI score and primary outcomes was presented as hazard ratios (HR) with 95% confidence intervals (CI) calculated by adverse events in the crude and multivariate-adjusted Cox Proportional Hazards models.Results Overall, adverse events were observed in 61(13%) patients. ROC curves revealed an area under curve of 0.676 for PNI with a cut-off of 46. The cumulative event rate by Kaplan–Meier analysis was higher in low PNI group (P < 0.001). Adjusted multivariate analysis showed that low PNI was associated with adverse outcomes (HR: 2.303, 95% CI: 1.338-3.964, P = 0.003). Conclusion Low PNI on admission in patients with SVR was associated with higher incidence of clinical adverse events. Using the PNI score to identify individuals with poor nutritional status might be an important method for clinical prognosis prediction, and improving nutritional status during follow-up might help to reduce the risks of adverse outcomes in these patients.