呼出气一氧化氮在咳嗽变异性哮喘诊断中的价值

Diagnostic value of fractional exhaled nitric oxide for cough variant asthma

摘要:

目的：探讨呼出气一氧化氮（fractional exhaled nitric oxide，FeNO）检测用于诊断咳嗽变异性哮喘（cough variant asthma，CVA）的临床价值及其影响因素。方法：连续收集2015年10月到2016年9月于我院就诊的慢性咳嗽患者607例，首先完成FeNO检测，之后通过支气管激发试验或支气管舒张试验并结合病史作为诊断CVA的标准，绘制FeNO诊断CVA的受试者工作特征曲线（receiver operating characteristic curve，ROC曲线），确定其最佳阈值；建立logisitic回归模型，通过模型分析筛选与CVA相关的因素，根据ROC曲线评价FeNO及FeNO联合其他相关因素对CVA的诊断价值。结果：607例患者中最终诊断CVA患者331例，非CVA患者276例。CVA组的FeNO水平明显高于非CVA组[（54.7±44.5） ppb vs. （19.8±11.9） ppb，P=0.000]；FeNO用于判定CVA的最佳阈值为31 ppb，约登指数最大值为0.507 6，ROC曲线下面积（area under curve，AUC）为0.794，此时检验的敏感度为61.63%，特异度为89.13%，阳性预测值为87.18%，阴性预测值为65.95%；年龄增高会引起FeNO下降，FeNO联合年龄、吸烟史诊断CVA的AUC为0.813，单用FeNO时的AUC为0.794，但两者差异无统计学意义（P=0.224）。结论：FeNO检测是诊断CVA的有效辅助手段，有助于慢性咳嗽的鉴别诊断；FeNO联合患者年龄、吸烟史诊断CVA价值不优于单用FeNO的诊断价值。

Abstract:

Objective：To explore the clinical value and possible influencing factors of fractional exhaled nitric oxide（FeNO） in patients with cough variant asthma（CVA）. Methods：Totally 607 patients with chronic cough consecutively referred to our hospital from October 2015 to September 2016 were selected. All cases were carried out FeNO measurement at first；next，spirometry，bronchoprovocation tests or bronchodilation tests and combining with the history were used to confirm or exclude CVA. Logistic regression model was established to analyze the factors associated with CVA. Receiver operating characteristic curve（ROC） was used to determine the best cut-off value of FeNO for CVA diagnosis and to evaluate the diagnostic value of FeNO and FeNO combined with other related factors in CVA. Results：Totally 331 cases were diagnosed as CVA and the other 276 cases were non-CVA. FeNO levels of CVA group were significantly higher than those of non-CVA group[（54.7±44.5） ppb vs. （19.8±11.9） ppb，P<0.01]. 31 ppb was the best cut-off value of FeNO identifying CVA with the sensitivity of 61.63% and the specificity of 89.13%. The area under ROC curve was 0.794. The maximum value of Youden’s index was 0.507 6. The positive predictive value was 87.18%，the negative predictive value was 65.95%. The increase of age caused the decrease of FeNO. The area under the ROC curve of FeNO combined with age and smoking history for diagnosing CVA was 0.813，which was slightly higher than the area under the ROC curve under the single use of FeNO，but the dif－ference between them was not statistically significant（P=0.224）. Conclusion：FeNO test is an effective auxiliary diagnosis method for CVA，which is helpful for the differential diagnosis of chronic cough. The diagnostic value of FeNO combined with other related factors for patients with CVA is not better than that of FeNO alone.