Unveiling the Utility of Fractional Exhaled Nitric Oxide (FeNO) in Asthma Diagnosis and Inflammatory Phenotyping: A Dissociation from Lung Function and Asthma Control

Unveiling the Utility of Fractional Exhaled Nitric Oxide (FeNO) in Asthma Diagnosis and Inflammatory Phenotyping: A Dissociation from Lung Function and Asthma Control | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Unveiling the Utility of Fractional Exhaled Nitric Oxide (FeNO) in Asthma Diagnosis and Inflammatory Phenotyping: A Dissociation from Lung Function and Asthma Control Jin Fenhua, Lin Hui, Yu Lihua, Huang Wen This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4380835/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective : This study aims to examine the association and clinical relevance of fractional exhaled nitric oxide (FENO) with lung function, sputum eosinophils, blood eosinophils, blood total IgE (TIgE), and asthma control test (ACT) score. Methods : A total of 189 participants, consisting of 99 asthmatic out-patients and 90 healthy individuals, were recruited for the study conducted between May 2013 and December 2013. The study aimed to investigate the correlation between various factors, including the levels of FeNO, FEV1%pred, ACT scores, sputum eosinophils, blood eosinophils, and TIgE, in asthma patients. Results : The results revealed that the levels of FeNO, blood eosinophils, and TIgE were significantly higher in asthma patients compared to healthy individuals (P<0.05). Additionally, the level of FEV1%pred was significantly lower in asthma patients compared to healthy individuals (P0.05），nor between FeNO level and ACT scores（r=-0.195，P>0.05）. Correlation analysis showed that，FENO level was positive correlated with sputum eosinophils（r=0.473, P<0.05）, blood eosinophils（r=0.315, P<0.05） and TIgE（r=0.305, P<0.05）. Conclusion : The FENO can assist diagnosis of asthma because the level of FENO is increased in asthma patients. FENO is no significant correlation with FEV1%Pred and ACT score, but the FENO level is positive correlated with sputum eosinophils, blood eosinophils and TIgE. FENO could reflect airway inflammatory level, especially esoinophilic airway inflammation. Asthma Fraction of exhaled nitric oxide Induced sputum Lung function Asthma control test Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Bronchial asthma is a chronic airway inflammation disease, and the monitoring of airway inflammation is crucial for guiding diagnosis, treatment, and prognosis. Fractional exhaled nitric oxide (FeNO) has emerged as a promising marker of airway inflammation due to its simplicity, non-invasiveness, and repeatability. [ 1 ] While global guidelines have recognized FeNO as a marker for asthma, there remains variability in its correlation with other clinical parameters, such as induced sputum, pulmonary function, and asthma control tests. [ 2 ] This study aims to investigate the correlation and clinical significance of FeNO with various markers of inflammation and asthma control. 2. Methods 2.1 Objectives The study aimed to assess the association of FeNO with induced sputum, pulmonary function, and asthma control in asthma patients. 2.2 Participants Participants were recruited from the Second Affiliated Hospital of Wenzhou Medical University between May 2013 and December 2013. Asthmatic patients aged 16–80 years and healthy controls were included in the study. Exclusion criteria for all participants included: (1) history of severe heart or other systemic diseases, (2) upper respiratory tract infection within 4 weeks, (3) inability to cooperate with FENO and pulmonary function tests, (4) females patients are pregnancy/lactation. The study protocol was approved by the institutional Ethics Committee, and all participants provided written informed consent. 2.3 Study Procedures Assessment of FeNO: FeNO levels were measured using the NIOX MINO analyzer according to recommended guidelines. [ 3 ] Pulmonary function test: Spirometry was performed to measure FEV1 percent predicted (FEV1% Pred). Induced sputum test: Induced sputum was collected and analyzed for inflammatory cell counts. [ 4 ] Asthma control test (ACT) score: ACT scores were obtained to assess asthma control. [ 2 ] Determination of peripheral blood eosinophil count and serum total IgE: Blood samples were collected and analyzed for eosinophil count and total IgE levels. 2.4 Statistical Analysis Data were analyzed using SPSS 26.0 software. Statistical tests included independent sample t-tests, chi-square tests, and Pearson's correlation analysis. 3. Results 3.1 General conditions : Ninety-nine asthmatic patients and 90 healthy controls were enrolled. Demographic characteristics of the two groups were shown in Table 1. Table 1. Comparison of basic characteristics between the two groups Number of cases Male（%） Age（years） BMI（kg/m2） Smoking（%） Asthma group 99 36(36.4) 40±12 24±3 17.2 Control group 90 39(43.3) 41±13 23±3 16.7 χ2/t 0.957 -0.710 1.865 0.092 P 0.328 0.478 0.064 0.927 As shown in Table 1, there were no statistically significant differences in gender, age, BMI and smoking history between the asthma group and the healthy control group. 3.2 FENO levels, FEV1 percent predicted (FEV1% Pred), blood eosinophil percentage (Eos%), and serum total IgE levels (TIgE) were compared between the two groups, as shown in Table 2. Table 2. Comparison of FENO, FEV1% Pred, blood Eos% and serum TIgE between the two groups (x ± s)) FENO（ppb） FEV1%Pred（%） Blood Eos%（%） TIgE（IU/ml） Asthma group 57±41 86.2±19.7 4.959±3.534 338.9±386.1 Control group 12±4 99.4±13.7 1.957±1.397 38.3±3.0 T 10.927 -5.261 6.724 6.861 P 0.000 0.000 0.000 0.000 As shown in Table 2, the FENO level, blood Eos% level and blood TIgE level in the asthma group were significantly higher than those in the healthy control group, and FEV1% Pred in the asthma group was significantly lower than that in the healthy control group. 3.3 According to the American Thoracic Society (ATS) clinical guidelines for FENO [5], FENO > 50 ppb is defined as high level (Grade 3), 50 ppb ≥ FENO ≥ 25 ppb as moderate level (Grade 2), and FENO < 25 ppb as low level (Grade 1). In the asthma group, 76% (71 patients) had FEV1 greater than 80% of predicted, including 47% (34 patients) with high levels of FENO. 3.4 Correlation analysis between FENO level and FEV1% Pred, ACT score, blood Eos%, blood TIgE and proportion of induced sputum eosinophils (sputum Eos%) in asthma group. There was no correlation between FeNO levels and FEV1% Pred in the asthma group (r = 0.004, P = 0.973),as shown in Figure 1； There was also no correlation between FeNO levels and ACT scores (r = -0.195, P = 0.053), as shown in Figure2. FeNO levels were positively correlated with blood EOS% (r = 0.315, P = 0.004 < 0.05), as shown in Figure 3. FeNO levels were positively correlated with blood TIgE (r = 0.305, P = 0.007 < 0.05), as shown in Figure 4. FeNO levels were positively correlated with induced sputum EOS% (r = 0.473, P = 0.004 < 0.05), as shown in Figure 5. 4. Discussion Asthma is a chronic inflammatory disease. Bronchoalveolar lavage and endobronchial biopsy can directly detect airway inflammation, but it is invasive procedure with certain risks as well as roor tolerance and repeatability of patients .So it is difficult to be widely carried out in clinical practice. In recent years, non-invasive airway inflammation detection technology has received extensive attention, including induced sputum detection, exhaled breath condensate detection, peripheral blood inflammatory indicators and FeNO determination. At present, there are few studies on the correlation between FENO levels and pulmonary function parameters, induced sputum, ACT scores, etc., and the conclusions drawn from different studies are different. In this study, we found that the FENO level in the asthma group was significantly higher than that in the control group, and the difference was statistically significant, consistent with the previous study [ 6 ], indicating that airway inflammation is significant in asthma patients and can be used as one of the auxiliary examinations for the diagnosis of asthma. Pulmonary ventilation function was also measured in asthmatic patients, and FEV1/pred levels were significantly lower in asthmatic patients than in controls. Reductions in FEV1 and FEV1/FVC are the most reliable indicators for evaluating airflow obstruction, but lung function can be normal in many asthmatic patients. Pulmonary function can objectively reflect the airway function of patients, and FENO can monitor airway inflammation in patients. In this study, there was no significant correlation between FENO level and FEV1% Pred in patients with asthma, which was consistent with some researches by domestic and foreign scholars [ 7 – 8 ], and it was found that some patients had no obstructive ventilatory dysfunction in pulmonary function, but FENO level was at a moderate to high level, which was consistent with foreign studies [ 9 ], indicating that patients had persistent airway inflammation and still needed active anti-inflammatory treatment. Therefore, the airway inflammatory response in asthma is not completely synchronous with the degree of airway obstruction, and the two reflect the condition of asthma from different aspects. However, Matsunaga K et al [ 10 ] have different reports and found that FeNO levels were negatively correlated with FEV1% Pred index of lung function. Therefore, the correlation between the two needs to be further verified by further studies with large samples. Asthma questionnaires such as ACT score are widely used in clinical practice, and different studies on the correlation between ACT score and FENO level have conflicting conclusions. Alvarez-Gutiérrez FJ et al. [ 11 ] studied 441 asthmatic patients and found a weak correlation between FENO levels and ACT scores (r = − 0.16, P < 0.01); study [ 7 ] showed a significant negative correlation between ACT scores and FENO levels (r = − 0.581, P < 0.0001). Consistent with the study by Khalili B [ 12 ],our study found no significant correlation between ACT score and FENO level in patients, which show that airway inflammation in asthma was not consistent with the patient 's clinical symptoms, and they may reflect different aspects of disease progression. Thus, even clinical symptoms of asthma are controlled and lung function returns to normal, airway inflammation may could always be present in asthma patients. In 1992, Pin et al [ 13 ] first used induced sputum to study airway inflammation in asthma and found that cytological examination of induced sputum could objectively reflect airway inflammation, and inflammatory markers of induced sputum could be used as indicators to measure the severity and severity of asthma. In this study, we found that the proportion of eosinophils in induced sputum was positively correlated with FENO levels, and the proportion of eosinophils in peripheral blood of asthmatic patients was significantly higher than that of controls, and the proportion of eosinophils in peripheral blood was also positively correlated with FENO levels, showing a close relationship between FENO and eosinophilic phenotype, which was consistent with previous studies [ 14 – 15 ]. Both FENO levels and eosinophil proportions in induced sputum can reflect airway inflammation in asthma, and multiple studies have shown a significant positive correlation between them. The purpose of long-term treatment of asthma is to reduce the symptoms of airway inflammation control, so FENO can be applied to asthma treatment to evaluate the efficacy and adjust the indicators of treatment options [ 16 ]. In addition, this study found that the serum total IgE level in the asthma group was significantly higher than that in the control group, and the study found that FeNO was positively correlated with the serum total IgE level, and the combination of the two could better assess the control of airway inflammation. 5. Conclusion FENO levels are significantly elevated in asthmatic patients and can assist in asthma diagnosis. There was no significant correlation between FENO and FEV1% Pred and ACT scores, indicating that the airway inflammatory response was not completely synchronous with the degree of airway obstruction, and the two reflected the condition of asthma from different aspects. The management of asthma cannot be satisfied only with the control of symptoms and lung function, and airway inflammation should be fundamentally controlled. FeNO can objectively reflect the level of airway inflammation, especially eosinophil inflammation in patients with asthma. FENO is positively correlated with the proportion of eosinophils in induced sputum and peripheral blood, and blood IgE level, which is of great significance for the diagnosis, treatment and evaluation of asthma. Declarations Ethics approval and consent to participate The protocol was approved by the second affiliated hospital of Wenzhou Medical university research ethics committee with certificate number L-2013-01. Written consent was provided for whom clinical and demographic data were extracted. Consent for publication Not Applicable. Availability of data and materials All data generated or analyzed during this study are included in this published article and its supplementary information file, additional file 1,2. Competing interests The Authors declare that there is no conflict of interest. Funding None. Authors' contributions Huang Wen and Jin fenhua researched literature and conceived the study. Lin hui an Yu Lihua was involved in protocol development, gaining ethical approval, patient recruitment and data analysis. Jin fenhua wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript. Acknowledgments Thanks to Ms. Feng for their assistance in data collection. DISCLOSURES We declare that we have no conflicts of interest. All authors made a substantial contribution to the information or material submitted for publication. All read and approved the final manuscript. References Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention. 2022. Available from: www.ginasthma.org. Asthma group of Chinese Throacic Society. Guidelines for bronchial asthma prevent and management(2020 edition)[J]. Chin J Tuberculosis Respiratory Dis 2020,43(12):1023–48. Sumita B, Khatri JM, Iaccarino A, Barochia, et al. Use of Fractional Exhaled Nitric Oxide to Guide the Treatment of Asthma: An Official American Thoracic Society Clinical Practice Guideline[J]. Am J Respir Crit Care Med. 2021;204(10):e97–109. Asthma group of Chinese Throacic Society. Chinese national guideline on diagnosis and management of cough(2021)[J]. Chin J Tuberculosis Respiratory Dis. 2022;45(1):13–46. Dweik RA. Boggs PB,Erzurum SC,An official ATS clinical practice guideline: Interpretation of exhaled nitric oxide levels (FENO) for clinical applications[J]. Am J Respiratory Crit Care Med 2011,184(5): 602–15. Wu Liqin,Li Zhixiong,Dai Yuanrong,et a1.Significance of fractional exhaled nitric oxide in the diagnosis of asthma in pregnant women[J]. Chin J Tuberculosis Respiratory Dis 2015,38(2):115–8. Habib SS. Alzoghaibi MA,Abba AA,et a1.Relationship of the Arabic version of the asthma control test with ventilatory function tests and levels of exhaled nitric oxide in adult asthmatics[J]. Saudi Med J 2014,35(4):397–402. Wu Liqin,Li Zhixiong,Dai Wei,et a1.Variability of fractional nitric oxide in women of different gestation periods and in asthmatic pregnant women[J]. Zhejiang Med J,2014,36(15):1294–320. Pijnenburg MW. Bakker EM,Hop WC,et a1.Titrating steroids on exhaled nitric oxide in children with asthma: a randomized controlled trial[J]. Am J Respir Crit Care Med 2005,172(7):831–6. Matsunaga K. Hirano T,Akamatsu K,et a1.Predictors for identifying the efficacy of systemic steroids on sustained exhaled nitric oxide elevation in severe asthma[J]. Allergol Int 2013,62(3):359–65. Alvarez-Gutiérrez FJ, Medina-Gallardo JF, Pérez-Navarro P et al. Comparison of the Asthma Control Test (ACT) with lung function, levels of exhaled nitric oxide and control according to the Global Initiative for Asthma (GINA)[J].Arch Bronconeumol,2010,46(7):370–7. Khalili B. Boggs PB,Shi R,Discrepancy between clinical asthma control assessment tools and fractional exhaled nitric oxide[J].Annals of Allergy. Asthma Immunol 2008,101(2):124–9. Pin I, Gibson PG, Kolendowicz R et al. Use of induced sputum cell counts to investigate airway inflammation in asthma[J].Thorax,1992,47(1):25–9. Jie Gao Z, Chen. Xiang Jie,et a1.Both fractional exhaled nitric oxide and sputum eosinophil were associated with uncontrolled asthma[J].J Asthma Allergy. 2018 Apr 10:11:73–9. Mohammed OA, Ghobain AS, Alsubaie. Walaa A Aljumah, et a1.The Correlation Between Fractional Exhaled Nitric Oxide (FeNO), Blood Eosinophil Count, Immunoglobulin E Levels, and Spirometric Values in Patients With. Asthma[J] Cureus. 2023;15(2):e35289. Hitasha Rupani 1. Brian D Kent. Using Fractional Exhaled Nitric Oxide Measurement in Clinical Asthma. Management[J] Chest. 2022;161(4):906–17. Additional Declarations No competing interests reported. Supplementary Files Supplementaryfileasthmagroup.xls Supplementaryfilenormalcontrolgroup.xls Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4380835","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":314560779,"identity":"8ab8b3c8-8b16-42cc-958d-78c8a8489a33","order_by":0,"name":"Jin Fenhua","email":"","orcid":"","institution":"the Second Affiliated Hospital of Wenzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jin","middleName":"","lastName":"Fenhua","suffix":""},{"id":314560780,"identity":"76d3a3b2-5e18-46b7-9f99-b54040ae55e8","order_by":1,"name":"Lin Hui","email":"","orcid":"","institution":"the Second Affiliated Hospital of Wenzhou 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4","display":"","copyAsset":false,"role":"figure","size":9828,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation analysis between FENO level and blood TIgE\u003c/p\u003e","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4380835/v1/138a6c7abb76f665a91ffefe.png"},{"id":59216401,"identity":"c74c1a1a-3d98-4da8-8387-f7684ce1d954","added_by":"auto","created_at":"2024-06-27 19:06:48","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":8348,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation analysis between FENO level and Eos% of induced sputum\u003c/p\u003e","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4380835/v1/b2a0d63ba36c54c97283a32a.png"},{"id":60610966,"identity":"fb043a92-5329-4090-9790-948207366245","added_by":"auto","created_at":"2024-07-18 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Introduction","content":"\u003cp\u003eBronchial asthma is a chronic airway inflammation disease, and the monitoring of airway inflammation is crucial for guiding diagnosis, treatment, and prognosis. Fractional exhaled nitric oxide (FeNO) has emerged as a promising marker of airway inflammation due to its simplicity, non-invasiveness, and repeatability. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] While global guidelines have recognized FeNO as a marker for asthma, there remains variability in its correlation with other clinical parameters, such as induced sputum, pulmonary function, and asthma control tests. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] This study aims to investigate the correlation and clinical significance of FeNO with various markers of inflammation and asthma control.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Objectives\u003c/h2\u003e \u003cp\u003eThe study aimed to assess the association of FeNO with induced sputum, pulmonary function, and asthma control in asthma patients.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Participants\u003c/h2\u003e \u003cp\u003e Participants were recruited from the Second Affiliated Hospital of Wenzhou Medical University between May 2013 and December 2013. Asthmatic patients aged 16\u0026ndash;80 years and healthy controls were included in the study. Exclusion criteria for all participants included: (1) history of severe heart or other systemic diseases, (2) upper respiratory tract infection within 4 weeks, (3) inability to cooperate with FENO and pulmonary function tests, (4) females patients are pregnancy/lactation. The study protocol was approved by the institutional Ethics Committee, and all participants provided written informed consent.\u003c/p\u003e \u003cp\u003e \u003cb\u003e2.3 Study Procedures\u003c/b\u003e \u003c/p\u003e \u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e Assessment of FeNO: FeNO levels were measured using the NIOX MINO analyzer according to recommended guidelines. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003ePulmonary function test: Spirometry was performed to measure FEV1 percent predicted (FEV1% Pred).\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eInduced sputum test: Induced sputum was collected and analyzed for inflammatory cell counts. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eAsthma control test (ACT) score: ACT scores were obtained to assess asthma control. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eDetermination of peripheral blood eosinophil count and serum total IgE: Blood samples were collected and analyzed for eosinophil count and total IgE levels.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Statistical Analysis\u003c/h2\u003e \u003cp\u003eData were analyzed using SPSS 26.0 software. Statistical tests included independent sample t-tests, chi-square tests, and Pearson's correlation analysis.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e3.1 General conditions : Ninety-nine asthmatic patients and 90 healthy controls were enrolled. Demographic characteristics of the two groups were shown in Table 1.\u003cbr\u003e\u0026nbsp;Table 1. Comparison of basic characteristics between the two groups\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eNumber of cases\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eMale（%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eAge（years）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.52577319587629%\"\u003e\n \u003cp\u003eBMI（kg/m2）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003eSmoking（%）\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003eAsthma group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e36(36.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003e40\u0026plusmn;12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.52577319587629%\" valign=\"top\"\u003e\n \u003cp\u003e24\u0026plusmn;3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e17.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003eControl group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e39(43.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003e41\u0026plusmn;13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.52577319587629%\" valign=\"top\"\u003e\n \u003cp\u003e23\u0026plusmn;3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e16.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026chi;2/t\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0.957\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003e-0.710\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.52577319587629%\" valign=\"top\"\u003e\n \u003cp\u003e1.865\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0.092\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0.328\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\" valign=\"top\"\u003e\n \u003cp\u003e0.478\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.52577319587629%\" valign=\"top\"\u003e\n \u003cp\u003e0.064\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"16.49484536082474%\"\u003e\n \u003cp\u003e0.927\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eAs shown in Table 1, there were no statistically significant differences in gender, age, BMI and smoking history between the asthma group and the healthy control group.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3.2 FENO levels, FEV1 percent predicted (FEV1% Pred), blood eosinophil percentage (Eos%), and serum total IgE levels (TIgE) were compared between the two groups, as shown in Table 2.\u003c/p\u003e\n\u003cp\u003eTable 2. Comparison of FENO, FEV1% Pred, blood Eos% and serum TIgE between the two groups (x \u0026plusmn; s))\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"104%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003eFENO（ppb）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003eFEV1%Pred（%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\"\u003e\n \u003cp\u003eBlood Eos%（%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003eTIgE（IU/ml）\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003eAsthma group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e57\u0026plusmn;41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e86.2\u0026plusmn;19.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\"\u003e\n \u003cp\u003e4.959\u0026plusmn;3.534\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003e338.9\u0026plusmn;386.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003eControl group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e12\u0026plusmn;4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e99.4\u0026plusmn;13.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\"\u003e\n \u003cp\u003e1.957\u0026plusmn;1.397\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003e38.3\u0026plusmn;3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003eT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e10.927\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e-5.261\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\"\u003e\n \u003cp\u003e6.724\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003e6.861\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.21212121212121%\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.19191919191919%\" valign=\"top\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eAs shown in Table 2, the FENO level, blood Eos% level and blood TIgE level in the asthma group were significantly higher than those in the healthy control group, and FEV1% Pred in the asthma group was significantly lower than that in the healthy control group.\u003c/p\u003e\n\u003cp\u003e3.3 According to the American Thoracic Society (ATS) clinical guidelines for FENO [5], FENO \u0026gt; 50 ppb is defined as high level (Grade 3), 50 ppb \u0026ge; FENO \u0026ge; 25 ppb as moderate level (Grade 2), and FENO \u0026lt; 25 ppb as low level (Grade 1). In the asthma group, 76% (71 patients) had FEV1 greater than 80% of predicted, including 47% (34 patients) with high levels of FENO.\u003c/p\u003e\n\u003cp\u003e3.4 Correlation analysis between FENO level and FEV1% Pred, ACT score, blood Eos%, blood TIgE and proportion of induced sputum eosinophils (sputum Eos%) in asthma group. There was no correlation between FeNO levels and FEV1% Pred in the asthma group (r = 0.004, P = 0.973),as shown in Figure 1；\u003c/p\u003e\n\u003cp\u003eThere was also no correlation between FeNO levels and ACT scores (r = -0.195, P = 0.053), as\u0026nbsp;shown in Figure2.\u003c/p\u003e\n\u003cp\u003eFeNO levels were positively correlated with blood EOS% (r = 0.315, P = 0.004 \u0026lt; 0.05), as shown in Figure 3.\u003c/p\u003e\n\u003cp\u003eFeNO levels were positively correlated with blood TIgE (r = 0.305, P = 0.007 \u0026lt; 0.05), as shown in Figure 4.\u003c/p\u003e\n\u003cp\u003eFeNO levels were positively correlated with induced sputum EOS% (r = 0.473, P = 0.004 \u0026lt; 0.05), as shown in Figure 5.\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eAsthma is a chronic inflammatory disease. Bronchoalveolar lavage and endobronchial biopsy can directly detect airway inflammation, but it is invasive procedure with certain risks as well as roor tolerance and repeatability of patients .So it is difficult to be widely carried out in clinical practice. In recent years, non-invasive airway inflammation detection technology has received extensive attention, including induced sputum detection, exhaled breath condensate detection, peripheral blood inflammatory indicators and FeNO determination. At present, there are few studies on the correlation between FENO levels and pulmonary function parameters, induced sputum, ACT scores, etc., and the conclusions drawn from different studies are different.\u003c/p\u003e \u003cp\u003eIn this study, we found that the FENO level in the asthma group was significantly higher than that in the control group, and the difference was statistically significant, consistent with the previous study [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], indicating that airway inflammation is significant in asthma patients and can be used as one of the auxiliary examinations for the diagnosis of asthma. Pulmonary ventilation function was also measured in asthmatic patients, and FEV1/pred levels were significantly lower in asthmatic patients than in controls. Reductions in FEV1 and FEV1/FVC are the most reliable indicators for evaluating airflow obstruction, but lung function can be normal in many asthmatic patients. Pulmonary function can objectively reflect the airway function of patients, and FENO can monitor airway inflammation in patients. In this study, there was no significant correlation between FENO level and FEV1% Pred in patients with asthma, which was consistent with some researches by domestic and foreign scholars [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], and it was found that some patients had no obstructive ventilatory dysfunction in pulmonary function, but FENO level was at a moderate to high level, which was consistent with foreign studies [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], indicating that patients had persistent airway inflammation and still needed active anti-inflammatory treatment. Therefore, the airway inflammatory response in asthma is not completely synchronous with the degree of airway obstruction, and the two reflect the condition of asthma from different aspects. However, Matsunaga K et al [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] have different reports and found that FeNO levels were negatively correlated with FEV1% Pred index of lung function. Therefore, the correlation between the two needs to be further verified by further studies with large samples.\u003c/p\u003e \u003cp\u003eAsthma questionnaires such as ACT score are widely used in clinical practice, and different studies on the correlation between ACT score and FENO level have conflicting conclusions. Alvarez-Guti\u0026eacute;rrez FJ et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] studied 441 asthmatic patients and found a weak correlation between FENO levels and ACT scores (r\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.16, P\u0026thinsp;\u0026lt;\u0026thinsp;0.01); study [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] showed a significant negative correlation between ACT scores and FENO levels (r\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.581, P\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Consistent with the study by Khalili B [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e],our study found no significant correlation between ACT score and FENO level in patients, which show that airway inflammation in asthma was not consistent with the patient 's clinical symptoms, and they may reflect different aspects of disease progression. Thus, even clinical symptoms of asthma are controlled and lung function returns to normal, airway inflammation may could always be present in asthma patients.\u003c/p\u003e \u003cp\u003eIn 1992, Pin et al [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] first used induced sputum to study airway inflammation in asthma and found that cytological examination of induced sputum could objectively reflect airway inflammation, and inflammatory markers of induced sputum could be used as indicators to measure the severity and severity of asthma. In this study, we found that the proportion of eosinophils in induced sputum was positively correlated with FENO levels, and the proportion of eosinophils in peripheral blood of asthmatic patients was significantly higher than that of controls, and the proportion of eosinophils in peripheral blood was also positively correlated with FENO levels, showing a close relationship between FENO and eosinophilic phenotype, which was consistent with previous studies [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Both FENO levels and eosinophil proportions in induced sputum can reflect airway inflammation in asthma, and multiple studies have shown a significant positive correlation between them. The purpose of long-term treatment of asthma is to reduce the symptoms of airway inflammation control, so FENO can be applied to asthma treatment to evaluate the efficacy and adjust the indicators of treatment options [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In addition, this study found that the serum total IgE level in the asthma group was significantly higher than that in the control group, and the study found that FeNO was positively correlated with the serum total IgE level, and the combination of the two could better assess the control of airway inflammation.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eFENO levels are significantly elevated in asthmatic patients and can assist in asthma diagnosis. There was no significant correlation between FENO and FEV1% Pred and ACT scores, indicating that the airway inflammatory response was not completely synchronous with the degree of airway obstruction, and the two reflected the condition of asthma from different aspects. The management of asthma cannot be satisfied only with the control of symptoms and lung function, and airway inflammation should be fundamentally controlled. FeNO can objectively reflect the level of airway inflammation, especially eosinophil inflammation in patients with asthma. FENO is positively correlated with the proportion of eosinophils in induced sputum and peripheral blood, and blood IgE level, which is of great significance for the diagnosis, treatment and evaluation of asthma.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe protocol was approved by the second affiliated hospital of Wenzhou Medical university research ethics committee with certificate number L-2013-01. Written consent was provided for whom clinical and demographic data were extracted.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article and its supplementary information file, additional file 1,2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Authors declare that there is no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHuang Wen\u0026nbsp;and\u0026nbsp;Jin fenhua\u0026nbsp;researched literature and conceived the study. Lin hui an Yu Lihua was involved in protocol development, gaining ethical approval, patient recruitment and data analysis.\u0026nbsp;Jin fenhua\u0026nbsp;wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThanks to Ms.\u0026nbsp;Feng\u0026nbsp;for their assistance in data collection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDISCLOSURES\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe declare that we have no conflicts of interest. All authors made a substantial contribution to the information or material submitted for publication. All read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGlobal Initiative for Asthma. Global Strategy for Asthma Management and Prevention. 2022. Available from: www.ginasthma.org.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAsthma group of Chinese Throacic Society. Guidelines for bronchial asthma prevent and management(2020 edition)[J]. Chin J Tuberculosis Respiratory Dis 2020,43(12):1023\u0026ndash;48.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSumita B, Khatri JM, Iaccarino A, Barochia, et al. Use of Fractional Exhaled Nitric Oxide to Guide the Treatment of Asthma: An Official American Thoracic Society Clinical Practice Guideline[J]. Am J Respir Crit Care Med. 2021;204(10):e97\u0026ndash;109.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAsthma group of Chinese Throacic Society. Chinese national guideline on diagnosis and management of cough(2021)[J]. Chin J Tuberculosis Respiratory Dis. 2022;45(1):13\u0026ndash;46.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDweik RA. Boggs PB,Erzurum SC,An official ATS clinical practice guideline: Interpretation of exhaled nitric oxide levels (FENO) for clinical applications[J]. Am J Respiratory Crit Care Med 2011,184(5): 602\u0026ndash;15.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu Liqin,Li Zhixiong,Dai Yuanrong,et a1.Significance of fractional exhaled nitric oxide in the diagnosis of asthma in pregnant women[J]. Chin J Tuberculosis Respiratory Dis 2015,38(2):115\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHabib SS. Alzoghaibi MA,Abba AA,et a1.Relationship of the Arabic version of the asthma control test with ventilatory function tests and levels of exhaled nitric oxide in adult asthmatics[J]. Saudi Med J 2014,35(4):397\u0026ndash;402.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu Liqin,Li Zhixiong,Dai Wei,et a1.Variability of fractional nitric oxide in women of different gestation periods and in asthmatic pregnant women[J]. Zhejiang Med J,2014,36(15):1294\u0026ndash;320.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePijnenburg MW. Bakker EM,Hop WC,et a1.Titrating steroids on exhaled nitric oxide in children with asthma: a randomized controlled trial[J]. Am J Respir Crit Care Med 2005,172(7):831\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMatsunaga K. Hirano T,Akamatsu K,et a1.Predictors for identifying the efficacy of systemic steroids on sustained exhaled nitric oxide elevation in severe asthma[J]. Allergol Int 2013,62(3):359\u0026ndash;65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlvarez-Guti\u0026eacute;rrez FJ, Medina-Gallardo JF, P\u0026eacute;rez-Navarro P et al. Comparison of the Asthma Control Test (ACT) with lung function, levels of exhaled nitric oxide and control according to the Global Initiative for Asthma (GINA)[J].Arch Bronconeumol,2010,46(7):370\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKhalili B. Boggs PB,Shi R,Discrepancy between clinical asthma control assessment tools and fractional exhaled nitric oxide[J].Annals of Allergy. Asthma Immunol 2008,101(2):124\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePin I, Gibson PG, Kolendowicz R et al. Use of induced sputum cell counts to investigate airway inflammation in asthma[J].Thorax,1992,47(1):25\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJie Gao Z, Chen. Xiang Jie,et a1.Both fractional exhaled nitric oxide and sputum eosinophil were associated with uncontrolled asthma[J].J Asthma Allergy. 2018 Apr 10:11:73\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMohammed OA, Ghobain AS, Alsubaie. Walaa A Aljumah, et a1.The Correlation Between Fractional Exhaled Nitric Oxide (FeNO), Blood Eosinophil Count, Immunoglobulin E Levels, and Spirometric Values in Patients With. Asthma[J] Cureus. 2023;15(2):e35289.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHitasha Rupani 1. Brian D Kent. Using Fractional Exhaled Nitric Oxide Measurement in Clinical Asthma. Management[J] Chest. 2022;161(4):906\u0026ndash;17.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Asthma, Fraction of exhaled nitric oxide, Induced sputum, Lung function, Asthma control test","lastPublishedDoi":"10.21203/rs.3.rs-4380835/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4380835/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e: This study aims to examine the association and clinical relevance of fractional exhaled nitric oxide (FENO) with lung function, sputum eosinophils, blood eosinophils, blood total IgE (TIgE), and asthma control test (ACT) score.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: A total of 189 participants, consisting of 99 asthmatic out-patients and 90 healthy individuals, were recruited for the study conducted between May 2013 and December 2013. The study aimed to investigate the correlation between various factors, including the levels of FeNO, FEV1%pred, ACT scores, sputum eosinophils, blood eosinophils, and TIgE, in asthma patients.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: The results revealed that the levels of FeNO, blood eosinophils, and TIgE were significantly higher in asthma patients compared to healthy individuals (P\u0026lt;0.05). Additionally, the level of FEV1%pred was significantly lower in asthma patients compared to healthy individuals (P\u0026lt;0.05).There was no significant correlation between FeNO 1evel and FEV1%Pred（r=0.004，P\u0026gt;0.05），nor between FeNO level and ACT scores（r=-0.195，P\u0026gt;0.05）. Correlation analysis showed that，FENO level was positive correlated with sputum eosinophils（r=0.473, P\u0026lt;0.05）, blood eosinophils（r=0.315, P\u0026lt;0.05） and TIgE（r=0.305, P\u0026lt;0.05）.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: The FENO can assist diagnosis of asthma because the level of FENO is increased in asthma patients. FENO is no significant correlation with FEV1%Pred and ACT score, but the FENO level is positive correlated with sputum eosinophils, blood eosinophils and TIgE. FENO could reflect airway inflammatory level, especially esoinophilic airway inflammation.\u003c/p\u003e","manuscriptTitle":"Unveiling the Utility of Fractional Exhaled Nitric Oxide (FeNO) in Asthma Diagnosis and Inflammatory Phenotyping: A Dissociation from Lung Function and Asthma Control","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-27 19:06:44","doi":"10.21203/rs.3.rs-4380835/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a4f8a8e1-0abf-45eb-85cc-f8f535a8d211","owner":[],"postedDate":"June 27th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-18T18:24:18+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-27 19:06:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4380835","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4380835","identity":"rs-4380835","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}