title: Association of longitudinal fractional exhaled nitric oxide measurements with asthma control in atopic children.
abstract: OBJECTIVE
  We sought to determine whether longitudinal measurements of FeNO are informative for future loss of asthma control in children with atopic asthma.
  
  
  METHODS
  One hundred seventy-eight patients aged 8-16 years with atopic asthma were enrolled. FeNO and lung functions were serially monitored 10 times or more over 2 years when subjects were not receiving controller medications. After completion of monitoring, 1-year observation on the occurrence of loss of asthma control was performed and associations of loss of asthma control with spirometric and FeNO measurements were analyzed.
  
  
  RESULTS
  Loss of asthma control occurred during observation periods in 110 (76%) of 145 patients who completed the study. Of all monitored parameters including airway reactivity, the highest FeNO of serial measurements (H-FeNO) (adjusted odds ratio (aOR), 1.21; 95% CI, 1.08-1.36) and the rate of FeNO levels higher than 21 ppb (R21FeNO) (aOR, 1.06; 95% CI, 1.01-1.11) were the only independent predictors of upcoming control loss in the multiple logistic regression analysis. In receiver-operator characteristic curve analysis, H-FeNO > 37 ppb and R21FeNO > 20% demonstrated 91% and 88% sensitivity for a future loss of asthma control at the cost of low specificity (60% and 65%, respectively). In contrast, H-FeNO > 47 ppb and R21FeNO > 41% gave 96% and 88% specificity, but these sacrificed sensitivity to 70% and 72%, respectively.
  
  
  CONCLUSIONS
  Our data show that both amount and frequency of a FeNO increase during longitudinal monitoring are helpful in predicting asthma control status.
authors.affiliation: Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.
authors.forename: Sohyoung
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.
authors.forename: Joohyun
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.
authors.forename: Youn Kyung
authors.initials: YK
authors.lastname: Lee
authors.affiliation: Department of Preventive Medicine, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea.
authors.forename: Heon
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Republic of Korea. Electronic address: yshahn@chungbuk.ac.kr.
authors.forename: Youn-Soo
authors.initials: YS
authors.lastname: Hahn
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000188:drug therapy* / Q000378:metabolism* / Q000503:physiopathology; D002648:Child; D045853:Exhalation / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D012372:ROC Curve; D012129:Respiratory Function Tests; D013147:Spirometry
chemical_list: D009569:Nitric Oxide
keywords: Asthma; Child; Fractional exhaled nitric oxide; Loss of asthma control; Lung function