title: Diagnostic accuracy of fractional exhaled nitric oxide measurement in predicting cough-variant asthma and eosinophilic bronchitis in adults with chronic cough: A systematic review and meta-analysis.
abstract: BACKGROUND
  Individual studies have suggested the utility of fractional exhaled nitric oxide (Feno) measurement in detecting cough-variant asthma (CVA) and eosinophilic bronchitis (EB) in patients with chronic cough.
  
  
  OBJECTIVE
  We sought to obtain summary estimates of diagnostic test accuracy of Feno measurement in predicting CVA, EB, or both in adults with chronic cough.
  
  
  METHODS
  Electronic databases were searched for studies published until January 2016, without language restriction. Cross-sectional studies that reported the diagnostic accuracy of Feno measurement for detecting CVA or EB were included. Risk of bias was assessed with Quality Assessment of Diagnostic Accuracy Studies 2. Random effects meta-analyses were performed to obtain summary estimates of the diagnostic accuracy of Feno measurement.
  
  
  RESULTS
  A total of 15 studies involving 2187 adults with chronic cough were identified. Feno measurement had a moderate diagnostic accuracy in predicting CVA in patients with chronic cough, showing the summary area under the curve to be 0.87 (95% CI, 0.83-0.89). Specificity was higher and more consistent than sensitivity (0.85 [95% CI, 0.81-0.88] and 0.72 [95% CI, 0.61-0.81], respectively). However, in the nonasthmatic population with chronic cough, the diagnostic accuracy to predict EB was found to be relatively lower (summary area under the curve, 0.81 [95% CI, 0.77-0.84]), and specificity was inconsistent.
  
  
  CONCLUSIONS
  The present meta-analyses indicated the diagnostic potential of Feno measurement as a rule-in test for detecting CVA in adult patients with chronic cough. However, Feno measurement may not be useful to predict EB in nonasthmatic subjects with chronic cough. These findings warrant further studies to validate the roles of Feno measurement in clinical practice of patients with chronic cough.
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Woo-Jung
authors.initials: WJ
authors.lastname: Song
authors.affiliation: Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ji-Su
authors.initials: JS
authors.lastname: Shim
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ha-Kyeong
authors.initials: HK
authors.lastname: Won
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sung-Yoon
authors.initials: SY
authors.lastname: Kang
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyoung-Hee
authors.initials: KH
authors.lastname: Sohn
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea; Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Byung-Keun
authors.initials: BK
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Pusan National University College of Medicine, Busan, Korea.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Jo
authors.affiliation: Department of Internal Medicine, Ewha Woman's University School of Medicine, Seoul, Korea.
authors.forename: Min-Hye
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: Sang-Heon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Heung-Woo
authors.initials: HW
authors.lastname: Park
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea; Department of Internal Medicine, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Korea.
authors.forename: Sun-Sin
authors.initials: SS
authors.lastname: Kim
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea; Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Yoon-Seok
authors.initials: YS
authors.lastname: Chang
authors.affiliation: Centre for Cardiovascular and Metabolic Research, Hull York Medical School, Castle Hill Hospital, University of Hull, Cottingham, United Kingdom.
authors.forename: Alyn H
authors.initials: AH
authors.lastname: Morice
authors.affiliation: Division of Allergy, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. Electronic address: leebj@skku.edu.
authors.forename: Byung-Jae
authors.initials: BJ
authors.lastname: Lee
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea; Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, Korea. Electronic address: shcho@snu.ac.kr.
authors.forename: Sang-Heon
authors.initials: SH
authors.lastname: Cho
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000378:metabolism*; D001991:Bronchitis / Q000175:diagnosis / Q000378:metabolism*; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis / Q000378:metabolism*; D004802:Eosinophilia / Q000175:diagnosis / Q000378:metabolism*; D045853:Exhalation; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide
keywords: Chronic cough; asthma; eosinophilic bronchitis; fractional exhaled nitric oxide; systematic review