title: Association between fractional exhaled nitric oxide (FeNO) cutoff values (25 ppb) and risk factors of cough.
abstract: BACKGROUND
  Cough is among the most common symptoms for patients to seek medical attention.
  
  
  OBJECTIVE
  The purpose of this study is to evaluate the association between fractional exhaled nitric oxide (FeNO) cutoff values (25 ppb) and risk factors related to cough, hoping to evaluate the feasibility of the FeNO cut point values (25 ppb) for clinical prediction of cough in etiology.
  
  
  METHODS
  In 107 adult patients with acute, subacute, or chronic cough, the FeNO, forced expiratory volume for 1 second (FEV1), forced vital capacity (FVC), blood routine (white blood cell and neutrophil), immunoglobulin E (IgE), lymphocyte eosinophils, and hemoglobin were measured. The Student's t-test was used to test the differences of FeNO levels compared with FEV1/FVC, lymphocyte, and hemoglobin level. For evaluating the correlation of FeNO levels with IgE, eosinophil, blood routine, pulmonary infection, and smoking status, the chi-square test was performed.
  
  
  RESULTS
  FeNO cutoff value (25 ppb) significantly correlated with serum IgE (P < .0001) between ≥200 IU/mL and <200 IU/mL level, eosinophil (P = .039) between ≥5% and <5% level, lymphocyte percentage (P = .032) and the ratio of FEV1/FVC (P = .032), while weakly correlated with pulmonary infection, blood routine (white blood cell and neutrophil), hemoglobin, and smoking.
  
  
  CONCLUSIONS
  The cutoff values of FeNO (≥25 ppb or <25 ppb) are useful for etiological detection of cough with high sensitivity.
authors.affiliation: Department of Respiratory Medicine, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Qian
authors.affiliation: Department of Respiratory Medicine, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
authors.forename: Shiying
authors.initials: S
authors.lastname: Pan
authors.affiliation: Department of Respiratory Medicine, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Respiratory Medicine, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Du
authors.affiliation: Department of Respiratory Medicine, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
authors.forename: Qihui
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Respiratory Medicine, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, 200240, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Jie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001944:Breath Tests; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D045853:Exhalation / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D012129:Respiratory Function Tests; D012307:Risk Factors; D014797:Vital Capacity; D055815:Young Adult
chemical_list: D009569:Nitric Oxide
keywords: clinical diagnose; cough; cutoff values; fractional exhaled nitric oxide