Abstract: Background　Community-acquired pneumonia（CAP）is one of the most important public health problems wordwide．The lower respiratory tract infections，represented by CAP，are reported to be the fourth leading cause of death worldwide.The assessment of disease severity and outcome prediction are necessary in the management of CAP．Objective　To assess the prognostic value of procalcitonin （PCT），CURB-65 score and pneumonia severity index （PSI） in patients with CAP．Methods　A total of 234 patients with CAP admitted to the East Region of the People's Hospital of Sichuan from June 2016 to June 2017 were enrolled in the study.According to the level of serum PCT within 6 hours of admission，patients were divided into group A （PCT<0.10 μg/L，106 cases），group B （0.10 μg/L≤PCT≤0.25 μg/L，39 cases），group C （0.25 μg/L<PCT≤0.50 ug/L，23 cases），and group D（PCT>0.50 μg/L，66 cases）．The CURB-65 score and PSI were used to assess the risk of death，serum PCT was detected，and the incidence of death and severe complications within 30 days were observed.Receiver operating characteristic （ROC） curve was used to analyze the predictive value of serum PCT，CURB-65 score and PSI.Results　The mortality and complication rate in group B，C and D were higher than those in group A （P<0.05），and the mortality and complication rate in group D were higher than those in group B and C （P<0.05）．The ROC curves of the mortality of CAP patients showed that the area under the ROC curve （AUC）of CURB-65 score  was 0.868 〔95%CI（0.797，0.939），P<0.001）〕；AUC of PSI was 0.894〔95%CI （0.851，0.948），P<0.001〕；the optimum critical value of PCT was 8.30 μg/L，AUC was 0.900〔95%CI （0.850，0.949），P<0.001〕；the AUC of PCT combined with CURB-65 score was 0.909〔95%CI （0.852，0.966），P<0.001〕 and that of PCT combined with PSI was 0.921〔95%CI （0.879，0.963），P<0.001〕.The ROC curves of complications in CAP patients showed that AUC of CURB-65 score was 0.815〔95%CI （0.727，0.903），P<0.001〕；AUC of PSI was 0.841〔95%CI （0.760，0.923），P<0.001〕；when the optimum critical value of PCT was 1.73 μg/L，AUC was 0.922〔95%CI （0.879，0.964），P<0.001〕；the AUC of PCT combined with CURB-65 score was 0.895〔95%CI （0.829，0.961），P<0.001〕 and that of PCT combined with PSI was 0.903〔95%CI （0.833，0.974），P<0.001〕.The AUC of PCT combined with CURB-65 score that predicted CAP complications was larger than that of CURB-65 score （Z=3.747，P=0.000 2）．Conclusion　Serum PCT can better predict the risk of death and complications of CAP.

Key words: Community-acquired pneumonia, Procalcitonin, CURB-65 score, Pneumonia severity index, Prognosis

摘要： 背景　社区获得性肺炎（CAP）是威胁人类健康的常见感染性疾病之一。以CAP为代表的下呼吸道感染是全球范围内病死率第4位疾病。故对CAP进行病情严重程度及预后评估极为重要。目的　评估血清降钙素原（PCT）、CURB-65评分及肺炎严重指数（PSI）在CAP预后中的预测价值。方法　选取2016年6月—2017年6月四川省人民医院（东院）呼吸科门诊收治的CAP患者234例，根据入院6 h内血清PCT水平分组，PCT<0.10 μg/L为A组（106例），0.10 μg/L≤PCT≤0.25 μg/L为B组（39例），0.25 μg/L<PCT≤0.50 μg/L为C组（23例），PCT>0.50 μg/L为D组（66例）。采用CURB-65评分、PSI评估死亡风险，检测血清PCT，并记录患者30 d内病死率及并发症发生率。采用受试者工作特征（ROC）曲线分析血清PCT、CURB-65评分、PSI的预测价值。结果　B、C、D组的病死率、并发症发生率均高于A组（P<0.05）；D组的病死率、并发症发生率均高于B、C组（P<0.05）。CAP患者死亡的ROC曲线结果显示，CURB-65评分的ROC曲线下面积（AUC）为0.868〔95%CI（0.797，0.939），P<0.001〕；PSI的AUC为0.894〔95%CI（0.851，0.948），P<0.001〕；PCT的最佳临界值为8.30 μg/L时，AUC为0.900〔95%CI（0.850，0.949），P<0.001〕；PCT联合CURB-65评分的AUC为0.909〔95%CI（0.852，0.966），P<0.001〕；PCT联合PSI的AUC为0.921〔95%CI（0.879，0.963），P<0.001〕。CAP患者并发症的ROC曲线结果显示，CURB-65评分的AUC为0.815〔95%CI（0.727，0.903），P<0.001〕；PSI的AUC为0.841〔95%CI（0.760，0.923），P<0.001〕；PCT的最佳临界值为1.73 μg/L时，AUC为0.922〔95%CI（0.879，0.964），P<0.001〕；PCT联合CURB-65评分的AUC为0.895〔95%CI（0.829，0.961），P<0.001〕；PCT联合PSI的AUC为0.903〔95%CI（0.833，0.974），P<0.001〕。PCT联合CURB-65评分预测CAP并发症的AUC大于CURB-65（Z=3.747，P=0.000 2）。结论　血清PCT可较好地预测CAP死亡及并发症风险。

关键词: 社区获得性肺炎, 降钙素原, CURB-65评分, 肺炎严重指数, 预后