Diagnostic Value Of FENO And Eosinophil In Asthma And Copd And Their Relationship Analysis

Background:Nearly 1-18%of the whole population suffer from asthma[1]and it’s incidence and burden will rise in coming decades[2].Asthma is a heterogenous disease and a complex pathophysiology plays a role in developing asthma.Several different phenotypes of asthma are identified and treatment module varies slightly for each of the phenotypes.Broadly asthma can be classified as eosinophilic or non-eosinophilic.In asthma airway inflammation plays a vital role.Spirometry is the classical diagnostic tool for diagnosing asthma.Nitric oxide is synthesized in airway by epithelial and other cells by the activity of the enzyme,Nitric oxide synthase(NOS).Fractional Exhaled Nitric Oxide(FeNO)is a noninvasive marker.It is economically sustainable and generally doesn’t require any expertise or special setup.Thus,evaluating the diagnostic value of FeNO for asthma and COPD and analyzing its relationship with the eosinophil holds an immense value.Aims&Objectives:1.To assess the value of the FeNO measurements in the diagnosis of asthma.2.To analyze the correlation of FeNO with eosinophil and IgE.3.To calculate the cut off value of FeNO to discriminate between the Asthmatic group&Non-asthmatic group.Method:About 241(113 Male&128 Female)consecutive subjects presenting with sign and symptoms suggestive of obstructive lung disease,who gave informed consent,were included in the study.Pulmonary function tests(PFT),Bronchial hyperresponsiveness(BHR),IgE,Eosinophils and FeNO were measured.Final diagnosis of the subjects with a classical approach was 77(32%)Asthma,95(39.4%)CVA,12(5%)COPD,7(2.9%)ACOS and 50(20.7%)Other respiratory disorders.With the help of software like Microsoft excel 2016&SPSS 25,data were interpreted.Quantitative data were expressed as mean and standard deviation.Qualitative data were expressed as frequency and as percentage.Comparision was done by "ANOVA test".Correlation between the markers were done by“Spearman rank analysis".Cut off value,sensitivity&specificity were determined by "ROC Curve".A probability(p)value of<0.05(p<0.05)was considered as statistically significant.Result:FeNO levels in Asthma 51.442 ppb(95%CI,46.3-56.6)were significantly higher than those in CVA 33.92 ppb(95%CI,29.327-38.53),COPD 22.3 ppb(95%CI,9.435.3),ACOS 16.6 ppb(95%CI,-0.37-33.5)and Others 17.84 ppb(95%CI,11.524.18).Eosinophil in the Asthma patient 0.33 × 109/L(95%CI,0.22-0.44)was significantly higher than in the CVA 0.29 × 109/L(95%CI,0.19-0.38),COPD 0.23 ×109/L(95%CI,-0.047-0.504),ACOS 0.320 × 109/L(95%CI,-0.040-0.680)and Others 0.08 × 109/L(95%CI,-0.47-0.627).IgE in the Asthma patient 370.96 IU/mL(95%CI,301.63-440.28),was significantly higher than CVA 61.734 IU/mL(95%CI,-0.190-123.65),COPD 98.74 IU/mL(95%CI,-74.580-272.04),ACOS 225.99 IU/mL(95%CI,-0.923-452.91)and Others 121.61 IU/mL(95%CI,-225.017-468.23).FeNO had significant positive correlations with IgE(r=0.332,p<0.001)and Eosinophils(r=0.344,p<0.001).The optimal cutoff level of FeNO was 26.5 ppb with sensitivity of 70%and specificity of 82.6%for distinguishing Asthmatics from Nonasthmatics.Conclusions:1.FeNO level can be used as a diagnostic tool for differentiating between Asthmatic and Non-asthmatics.2.FeNO significantly positively correlates with Eosinophil&IgE.