Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, China.
Am J Med Sci. 2013 Mar;345(3):190-4. doi: 10.1097/MAJ.0b013e318253c921.
Chronic obstructive pulmonary disease (COPD) causes a high rate of morbidity worldwide and predicting a bacterial cause of an exacerbation of COPD is difficult.
In this study, patient serum was obtained and C-reactive protein (CRP) levels were measured using an automated latex-enhanced turbidimetric assay. Sputum samples were obtained and evaluated microscopically. The relationship between CRP and the bacterial colonies in sputum in 81 patients with an exacerbation of COPD was assessed. Receiver operating characteristic (ROC) curves and the respective areas under the curve (AUCs) were calculated. Data from 64 patients with bacterial acute exacerbation of COPD (AECOPD) were compared with those of 37 patients with no documented bacterial AECOPD. Results categorized according to the nature of sputum as mucoid or purulent were also compared.
High median CRP levels were observed in bacterial AECOPD compared with nonbacterial AECOPD. The ideal cutoff point for distinguishing patients with bacterial AECOPD from those with nonbacterial AECOPD was 19.65 mg/L (sensitivity, 78.18%; specificity, 84.61%; AUC, 0.832). In patients with mucoid sputum, the cutoff point was 15.21 mg/L and the area under the ROC curve 0.86, with a sensitivity of 81.5% and a specificity of 77.8%. Purulent sputum had a significantly higher CRP level than mucoid sputum, but with an AUC of only 0.617 (95% confidence interval, 0.49-0.74) to diagnosis bacterial AECOPD.
In adult patients with symptoms of AECOPD, an elevated serum CRP level of >19.6 mg/L indicates bacterial exacerbation. In patients with AECOPD with mucoid sputum, an elevated CRP level of >15.21 mg/L indicates bacterial infection, which may be a useful clinical marker for therapy of this disease.
慢性阻塞性肺疾病（COPD）在全球范围内导致高发病率，预测 COPD 加重的细菌病因较为困难。
本研究中，采集患者血清并使用自动乳胶增强比浊法测量 C 反应蛋白（CRP）水平。采集痰标本并进行显微镜评估。评估 81 例 COPD 加重患者的 CRP 与痰中细菌菌落之间的关系。计算受试者工作特征（ROC）曲线和相应的曲线下面积（AUCs）。将 64 例细菌急性加重的 COPD（AECOPD）患者的数据与 37 例无细菌 AECOPD 记录的患者进行比较。还比较了根据痰的性质分类为黏液性或脓性的结果。
与非细菌性 AECOPD 相比，细菌性 AECOPD 患者的 CRP 中位数水平较高。区分细菌性 AECOPD 患者和非细菌性 AECOPD 患者的最佳截断值为 19.65mg/L（敏感性为 78.18%，特异性为 84.61%，AUC 为 0.832）。在黏液性痰患者中，截断值为 15.21mg/L，ROC 曲线下面积为 0.86，敏感性为 81.5%，特异性为 77.8%。脓性痰的 CRP 水平明显高于黏液性痰，但诊断细菌性 AECOPD 的 AUC 仅为 0.617（95%置信区间为 0.49-0.74）。
在出现 AECOPD 症状的成年患者中，血清 CRP 水平升高>19.6mg/L 提示细菌加重。在 AECOPD 患者中，CRP 水平升高>15.21mg/L 提示细菌感染，这可能是治疗该疾病的有用临床标志物。
