Neutrophil-to-lymphocyte ratio as a feasible prognostic marker for pyogenic liver abscess in the emergency department

Purpose: The neutrophil-to-lymphocyte ratio (NLR) is an effective predictor of mortality in patients with for various conditions. To date, there are no previous studies on NLR as a prognostic marker for pyogenic liver abscess (PLA), especially on admission to the emergency department (ED). Methods: From January 2013 to December 2015, 102 patients diagnosed with PLA in the ED were included. Clinico-radiological and laboratory results, including NLR, were evaluated as variables. NLR was calculated as absolute neutrophil count/absolute lymphocyte count. To evaluate the prognosis of PLA, data on hospital mortality, intensive care unit (ICU) admission, and development of septic shock were obtained. Multivariate logistic regression analyses and receiver-operating characteristic (ROC) curve analysis were performed. Results: Among 102 patients, 10 (9.8%) died, 14 (13.7%) were admitted to the ICU, and 15 (14.7%) developed septic shock during hospitalization. Multivariate logistic regression analysis revealed NLR as an independent factor in predicting death [odds ratio (OR), 1.4; p = 0.020], ICU admission (OR, 1.4; p = 0.021), and development of septic shock (OR, 1.6; p = 0.041). NLR showed an excellent predictive performance for death (areas under the ROC curves [AUC], 0.941; cut-off value, 19.7; p < 0.001), ICU admission (AUC, 0.946; cut-off value, 16.9; p < 0.001), and development of septic shock (AUC, 0.927; cut-off value, 16.9; p < 0.001). Conclusion: NLR was positively associated with poor prognosis of PLA; elevated NLR could predictor of high risk of death, ICU admission, and development of septic shock. Emergency physicians should consider NLR for the prognosis of PLA and early aggressive treatment, especially in patients with NLR > 16.9.