Flood Robert G, Badik Jennifer, Aronoff Stephen C
Department of Pediatrics, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Pediatr Infect Dis J. 2008 Feb;27(2):95-9. doi: 10.1097/INF.0b013e318157aced.
Differentiating bacterial from nonbacterial community-acquired pneumonia in children is difficult. Although several studies have evaluated serum concentrations of C-reactive protein (CRP) as a predictor of bacterial pneumonia in this patient population, the utility of this test remains unclear.
The purpose of this meta-analysis was to quantitatively define the utility of serum CRP as a predictor of bacterial pneumonia in acutely ill children.
Multiple databases were searched, bibliographies reviewed, and 2 authorities in the field were queried. Studies were included if: (1) the patient population was between 1 month and 18 years of age; (2) CRP was quantified in all subjects as part of the initial evaluation of a suspected, infectious, pulmonary process; (3) a cutoff serum CRP concentration between 30 and 60 mg/dL was used to distinguish nonbacterial from bacterial pneumonia; (4) some criteria were applied to differentiate bacterial from nonbacterial or viral pneumonia; (5) all patients were acutely ill; and (6) a chest radiograph was obtained as part of the initial evaluation. The quality of each included study was determined across 4 metrics: diagnostic criteria; study design; exclusion of chronically ill or human immunodeficiency virus infected subjects; and exclusion of patients who recently received antibiotics. Data was extracted from each article; the primary outcome measure was the odds ratio of patients with bacterial or mixed etiology pneumonia and serum CRP concentrations exceeding 30-60 mg/L. Heterogeneity among the studies was determined by Cochran's Q statistic; the methods of both Mantel and Haenszel, and DerSimonian and Laird were used to combine the study results.
Eight studies fulfilled inclusion criteria. Combining all of the studies demonstrated a pooled study population of 1230 patients with the incidence of bacterial infection of 41%. Children with bacterial pneumonia were significantly more likely to have serum CRP concentrations exceeding 35-60 mg/L than children with nonbacterial infections (odds ratio = 2.58, 95% confidence interval = 1.20-5.55). Sensitivity analysis demonstrated that this difference was robust. There was significant heterogeneity among the 8 studies (Q = 37.7, P < 0.001, I2 = 81.4) that remained throughout the sensitivity analysis.
In children with pneumonia, serum CRP concentrations exceeding 40-60 mg/L weakly predict a bacterial etiology.
区分儿童细菌性与非细菌性社区获得性肺炎很困难。尽管有多项研究评估了血清C反应蛋白（CRP）浓度作为该患者群体细菌性肺炎的预测指标，但该检测的效用仍不明确。
本荟萃分析的目的是定量确定血清CRP作为急性病患儿细菌性肺炎预测指标的效用。
检索了多个数据库，查阅了参考文献，并咨询了该领域的2位权威人士。纳入的研究需满足以下条件：（1）患者年龄在1个月至18岁之间；（2）作为疑似感染性肺部疾病初始评估的一部分，对所有受试者进行CRP定量检测；（3）使用30至60mg/dL的血清CRP浓度临界值来区分非细菌性肺炎和细菌性肺炎；（4）应用某些标准来区分细菌性肺炎与非细菌性肺炎或病毒性肺炎；（5）所有患者均为急性病患者；（6）作为初始评估的一部分进行胸部X光检查。根据4项指标确定每项纳入研究的质量：诊断标准；研究设计；排除慢性病患者或人类免疫缺陷病毒感染患者；排除近期接受过抗生素治疗的患者。从每篇文章中提取数据；主要结局指标是细菌性或混合病因肺炎患者以及血清CRP浓度超过30 - 60mg/L的患者的比值比。通过Cochran's Q统计量确定研究间的异质性；使用Mantel和Haenszel法以及DerSimonian和Laird法合并研究结果。
8项研究符合纳入标准。综合所有研究显示，共有1230名患者参与研究，其中细菌感染发生率为41%。与非细菌感染患儿相比，细菌性肺炎患儿血清CRP浓度超过35 - 60mg/L的可能性显著更高（比值比 = 2.58，95%置信区间 = 1.20 - 5.55）。敏感性分析表明这种差异是可靠的。8项研究之间存在显著异质性（Q = 37.7，P < 0.001，I² = 81.4），且在整个敏感性分析过程中一直存在。
在肺炎患儿中，血清CRP浓度超过40 - 60mg/L对细菌性病因的预测作用较弱。
