title: Exhaled nitric oxide predicts eosinophilic airway inflammation in COPD.
abstract: OBJECTIVE
  Chronic obstructive pulmonary disease (COPD) with eosinophilic airway inflammation may represent a unique phenotype, possibly with shared features of COPD and asthma. The role of exhaled nitric oxide (eNO) in identifying COPD patients with sputum eosinophilia was examined in this study.
  
  
  METHODS
  Ninety COPD patients without past medical history of asthma or allergic diseases were prospectively enrolled, and their eNO, lung function, and cellular profile of induced sputum were measured. Eosinophil cationic protein and IgE in sputum and venous blood also were determined. Subjects with and without sputum eosinophilia (>3 %) were compared. The role of eNO in the prediction of sputum eosinophilia was assessed in a logistic regression model.
  
  
  RESULTS
  Patients with sputum eosinophilia had significantly higher levels of eNO (29 vs. 18 ppb, p = 0.01) than those without. The difference in serum total IgE (168 vs. 84.9 IU/ml, p = 0.057) and percentages of positive allergen test results (48.3 vs. 29.5 %, p = 0.082) showed a trend toward significance. The sputum eosinophil level was significantly correlated to the eNO level (r = 0.485, p < 0.001). The eNO level at the cutoff of 23.5 ppb had the maximum sum of sensitivity (62.1 %) and specificity (70.5 %). The unadjusted and adjusted odds ratios of a higher eNO level (>23.5 ppb) in the prediction of sputum eosinophilia were 3.909 (confidence interval (CI) 1.542-9.91, p = 0.004) and 4.329 (CI 1.306-14.356, p = 0.017), respectively.
  
  
  CONCLUSIONS
  eNO is a good marker to identify COPD patients with eosinophilic airway inflammation.
authors.affiliation: Department of Chest Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shi-Pai Road, Taipei, 112, Taiwan.
authors.forename: Kun-Ta
authors.initials: KT
authors.lastname: Chou
authors.forename: Kang-Cheng
authors.initials: KC
authors.lastname: Su
authors.forename: Shiang-Fen
authors.initials: SF
authors.lastname: Huang
authors.forename: Yi-Han
authors.initials: YH
authors.lastname: Hsiao
authors.forename: Ching-Min
authors.initials: CM
authors.lastname: Tseng
authors.forename: Vincent Yi-Fong
authors.initials: VY
authors.lastname: Su
authors.forename: Shih-Chieh
authors.initials: SC
authors.lastname: Hung
authors.forename: Diahn-Warng
authors.initials: DW
authors.lastname: Perng
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D047150:Eosinophil Cationic Protein / Q000378:metabolism; D045853:Exhalation; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D016015:Logistic Models; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D016017:Odds Ratio; D011014:Pneumonia / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D011657:Pulmonary Eosinophilia / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D012372:ROC Curve; D012129:Respiratory Function Tests; D013183:Sputum / Q000166:cytology / Q000378:metabolism
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide; D007073:Immunoglobulin E; D047150:Eosinophil Cationic Protein; C479220:RNASE3 protein, human