title: [High fractional exhaled nitric oxide may predict response to inhaled corticosteroid therapy in patients with subacute cough].
abstract: OBJECTIVE
  To evaluate fractional exhaled nitric oxide (FENO) level in patients with subacute cough and its value in predicting the patients' response to inhaled corticosteroids (ICS) treatment.
  
  
  METHODS
  A total of 100 patients with persistent cough lasting more than 3 weeks were enrolled, including 52 patients with subacute cough and 48 with chronic cough. FENO, spirometry, and responses to ICS therapy of the patients were evaluated.
  
  
  RESULTS
  The recruited patients had a median (inter-quartile ranges) FENO level of 19 ppb (12-30 ppb). Patients with chronic cough had a significantly higher median FENO level than those with subacute cough (20.5 vs 16 ppb; Z=-2.245, P=0.025). A FENO level ≥25 ppb was recorded in 15 (28.8%) patients with subacute cough, as compared with 20 (41.6%) in patients with chronic cough (χ(2)=1.801, P=0.179). With a FENO ≥25 ppb as the critical value to justify ICS treatment, 15 patients with subacute cough received ICS and 14 (93.3%) of them showed obvious relief of cough after 2 weeks of therapy, a response rate similar to that of 85.0% (17/20) in patients with chronic cough receiving the treatment (χ(2)=0.588, P=0.443). In patients with subacute cough, those with cough variant asthma (CVA) or eosinophilic bronchitis (EB) had a significantly higher median FENO level than those with postinfectious cough [(16 (11-31) ppb vs 11 (8-19) ppb, P<0.01]. In the etiological analysis, CVA or EB was identified in 23 (44.2%) of the patients with subacute cough, as compared 21 (43.8%) in patients with chronic cough (χ(2)=0.002, P=0.961).
  
  
  CONCLUSIONS
  FENO may be an important indicator for etiological diagnosis of subacute cough and for predicting the response to ICS treatment.
authors.affiliation: Chronic Airway Diseases Laboratory, Department of Respiratory and Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.E-mail: coco920wei@163.com.
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Ye
authors.forename: Yan-Hong
authors.initials: YH
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Ni
authors.forename: Jian-Peng
authors.initials: JP
authors.lastname: Liang
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Yu
authors.forename: Yue-Xian
authors.initials: YX
authors.lastname: Wu
authors.forename: Wen-Qu
authors.initials: WQ
authors.lastname: Zhao
authors.forename: Jing
authors.initials: J
authors.lastname: Xiong
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Yao
authors.forename: Shao-Xi
authors.initials: SX
authors.lastname: Cai
authors.forename: Hai-Jin
authors.initials: HJ
authors.lastname: Zhao
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D001944:Breath Tests; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis / Q000188:drug therapy*; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*
chemical_list: D000305:Adrenal Cortex Hormones; D009569:Nitric Oxide