Background. Infective endocarditis (IE) is a complex infectious disease with high morbidity and mortality. The inflammation mechanism of IE is a complex network including interactions of inflammatory cytokines and other components of host response. As an important inflammation marker, the prediction ability of neutrophil-to-lymphocyte ratio (NLR) in IE deserves further investigation. Methods. NLR values were measured and compared between IE patients and healthy controls, good and bad clinical outcome groups. The receiver operating characteristic curves (ROCs) of NLR and cut-off values were measured in IE patients, pathogen-subgroups, and different clinical outcome groups. Results. There were 678 IE patients and 2520 healthy controls enrolled in our study. The number of good and bad clinical outcome patients was 537 and 141, respectively. The value of NLR was significantly higher in IE patients than healthy controls ( vs. , ), and the area under the ROC (AUC) was 0.817 (95% CI (0.794, 0.839), ). The critical value of NLR for diagnosis of IE was 2.68, with a sensitivity of 69%, and a specificity of 88%. The value of NLR was significantly higher in bad clinical outcome patients than in good clinical outcome patients ( vs. , ). The critical value of NLR to predict the outcome of IE was 5.557, with a sensitivity of 39.0% and a specificity of 85.3%. Conclusions. NLR is a predictive marker for IE patients, especially in Gram-negative bacteria and Gram-positive bacteria-infected IE patients. NLR also can predict the outcome of IE. Early detecting NLR upon admission may assist in early diagnosis and risk stratification of patients with IE.

中文翻译：

---

预测感染性心内膜炎的中性粒细胞-淋巴细胞比值：病例对照回顾性研究

背景。感染性心内膜炎（IE）是一种复杂的传染病，发病率和死亡率都很高。IE的炎症机制是一个复杂的网络，包括炎症细胞因子和宿主反应的其他成分的相互作用。作为重要的炎症标志物，中性粒细胞与淋巴细胞比率（NLR）在IE中的预测能力值得进一步研究。方法。NLR 值在 IE 患者和健康对照组、临床结果组的好坏组之间进行测量和比较。在 IE 患者、病原体亚组和不同临床结果组中测量 NLR 的受试者工作特征曲线 (ROC) 和临界值。结果. 我们的研究纳入了 678 名 IE 患者和 2520 名健康对照。临床结果良好和不良的患者数量分别为 537 和 141。IE患者的NLR值显着高于健康对照组（对比, ), ROC 下面积 (AUC) 为 0.817 (95% CI (0.794, 0.839),）。NLR诊断IE的临界值为2.68，敏感性为69%，特异性为88%。NLR 值在临床预后不良的患者中显着高于临床预后良好的患者（对比, ）。NLR预测IE结局的临界值为5.557，敏感性为39.0%，特异性为85.3%。结论。NLR 是 IE 患者的预测标志物，特别是在革兰氏阴性菌和革兰氏阳性菌感染的 IE 患者中。NLR 还可以预测 IE 的结果。入院时早期检测 NLR 可能有助于 IE 患者的早期诊断和风险分层。