FeNO Measurement In Diagnosing And Guiding Treatment In Asthma, And Study The Correlation With EDN

Objective: To assess the value of FeNO in diagnosing in suspected patients，guiding thetreatment in patients with newly diagnosed asthma,and the correlation with EDN.Method: We included222cases of suspected asthma patients with wheezing, chesttightness or cough from August2012to December2013. The patients received FeNO testby nitric oxide analyzer（FeNO），based on clinical symptoms and bronchial provocationtest or dilation test as the gold standard for the diagnosis of asthma. Different FeNOmeasurements corresponds to different degrees of sensitivity and specificity. We evaluatedthe diagnostic value and the optimal cutoff of FeNO by the means of the receiver operatingcharacteristic（ROC）curves.65patients of newly diagnosed asthma and23healthysubjects were enrolled into our study,detected and compared the serum EDN levels byenzyme-linked immunosorbent assay (ELISA),by the meanwhile,the asthma groupreceived FeNO test,we studied the correlation between FeNO,FEV1/predict%and EDNthrough Person correlation Analysis.116cases of newly-diagnosed patients with asthma,had FeNO test and Asthma Control Questionnaire (ACT), grouped according to FeNOlevels, FeNO≥50ppb for the high-level group (46cases),50ppb-25ppb for the moderategroup (44cases), FeNO≤25ppb the low group (26cases), all patients regularly inhaledGlucocorticoid combined long-acting β2agonists,12weeks later reviewed FeNO and ACTscore.Results: Of all the222patients,130cases were diagnosed as asthma，and92cases werediagnosed as non‐asthmatics．The area under the ROC curve was0.888（95%CI：0.844-0.931，P＜0.0001）．The optimal FeNO cutoff value was40ppb with a sensitivity of78.5%，a specificity of92.4%,a positive predictive value of94.79%，a negative predictivevalue of69.05%. The concentration of EDN between asthma group and the normal was (42.46±6.476vs21.32±7.088ng/ml, P<0.0001), there was significantly positivecorrelation between FENO and EDN in asthma group (r2=0.3742, P <0.0001),but not inEDN and FEV1/predict%. Before treatment, the FeNO level negatively correlated withACT score (r=-0.455, P <0.0001), after treatment was not (r=-0.171, P=0.066); Thethree groups FeNO decreased after treatment, high and moderate level group decreasedsignificantly (t=16.83, t=14.53, P<0.0001), low level group did not (t=2.030, P=0.054);After treatment according to the ACT score we judged whether control or not,high、moderate and low group control rates were81.4%,72.5%,44.0%, high and moderategroup the control rates showed no difference (x2=0.93, P>0.05), but moderate and lowlevel group was significantly different (x2=5.28, P <0.05).Conclusion:FeNO test is of high value in the diagnosis of asthma, identifing the type ofairway inflammation,and at the same time predicting the effect of glucocorticoidtreatment.