目的 在急诊老年社区获得性肺炎（community-acquired pneumonia，CAP）住院患者中建立一个客观、准确的预后模型来评估严重程度以及预后情况。 方法 回顾性分析2018年6月至2020年12月期间在复旦大学附属闵行医院急诊科住院的老年CAP患者。以老年CAP患者30天住院死亡率为主要结局，将4种全身炎症反应标志物中性粒细胞与淋巴细胞计数比值（neutrophil-to-lymphocyte ratio，NLR）、单核细胞与淋巴细胞计数比值（monocyte-to-lymphocyte ratio，MLR）、血小板与淋巴细胞计数比值（platelet-to-lymphocyte ratio，PLR）、系统免疫炎症指数（systemic immune inflammation index，SII）纳入单因素和多因素Logistic回归分析，并比较不同评分系统的预测性能。 结果 最终纳入421例老年CAP患者。多因素Logistic回归分析结果表明NLR是老年CAP住院患者的独立危险因素。将NLR与CURB-65评分联合优化构建评分系统，根据NLR最佳截断值11.4对该变量进行量化赋后，建立NLR+CURB-65评分。构建ROC曲线来比较3种不同评分系统（NLR、CURB-65、NLR+CURB-65）的曲线下面积，发现NLR+CURB-65评分的曲线下面积明显高于CURB-65评分。根据NLR+CURB-65评分的最佳截断值3，将患者进行分层，≥3分为高危组（n=188），<3分为低危组（n=233）。K-M生存曲线分析表明与高危组相比，低危组患者的死亡率更低、出院率更高。 结论 对于急诊老年CAP住院患者，NLR+CURB-65评分对其病情严重程度以及预后的预测能力具有较高价值。

Objective To develop an objective and precise prognostic model for assessing severity and prognosis in elderly patients with community-acquired pneumonia （CAP） admitted to the emergency department. Methods A retrospective analysis was conducted on elderly patients with CAP admitted to Department of Emergency， Minhang Hospital， Fudan University between Jun 2018 and Dec 2020. With the primary outcome being the 30-day in-hospital mortality rate of elderly CAP patients， four systemic inflammatory response markers， including the neutrophil-to-lymphocyte ratio （NLR）， monocyte-to-lymphocyte ratio （MLR）， platelet-to-lymphocyte ratio （PLR）， and systemic immune-inflammation index （SII） were evaluated using univariate and multivariate Logistic regression analyses. The predictive performance of different scoring systems was compared. Results A total of 421 elderly CAP cases were enrolled. The results of the multivariate Logistic regression analysis demonstrated that NLR was an independent risk factor for elderly inpatients with CAP. We combined NLR with the existing CURB-65 score for joint optimization to construct a scoring system or a clinical prognosis model， by quantifying and assigning optimal cut-off value of 11.4 for NLR， and established the NLR+CURB-65 score. The ROC curve was constructed to compare the areas under the curve of the three different scoring systems （NLR， CURB-65， and NLR+CURB-65）. The area under the curve of the NLR+CURB-65 score was significantly higher than that of the CURB-65 score. Based on the optimal cut-off value of 3 for NLR+CURB-65 score， the patients were stratified into high-risk group （n=188） and low-risk group （n=233）. The K-M survival curve was utilized and indicated that compared with high-risk group， low-risk group had a lower mortality rate and a higher discharge rate. Conclusion For elderly emergency hospitalized patients with CAP， the combination of NLR and CURB-65 score showed high predictive value for assessing disease severity and prognosis.