title: Spirometry-Adjusted Fraction of Exhaled Nitric Oxide Allows Asthma Diagnosis in Children, Adolescents, and Young Adults.
abstract: BACKGROUND
  Recently, it has been proved that fractional exhaled nitric oxide (FENO) results are in disagreement with other measurements of asthma control. The objective of this work is to present and validate new lung function/lung inflammation ratios.
  
  
  METHODS
  This is a retrospective, cross-sectional study in which we evaluated data from medical documentation of 1,529 pediatric and adolescent subjects and a small number (2% of the studied population) of young adults, who presented symptoms suggestive of asthma (age range 4-24 y). We are the first to analyze results obtained in this manner (before the introduction of controlled medication): FENO, spirometry, specific resistance of the airways, diagnosis of allergic diseases, and allergen sensitization (specific immunoglobulin E results).
  
  
  RESULTS
  Cut-off points for the new indicators allowed us to diagnose asthma in the study participants: for FVC/FENO ratio, 0.17 L/ppb; for FEV1/FENO ratio, 0.15 L/ppb; for forced expiratory flow during the middle half of the FVC maneuver (FEF25-75%)/FENO ratio, 0.16 L/s/ppb; for FENO/FVC ratio, 11.00 ppb/L; for FENO/FEV1 ratio, 12.53 ppb/L; and for FENO/FEF25-75% ratio, 11.81 ppb/L/s. Only the ratios described above were closely correlated with the diagnosis of asthma and with one another. They significantly differed between subjects with asthma and healthy subjects as well as between females and males. Only FEF25-75%/FENO and FENO/FEF25-75% values were significant predictors of any sensitization in the studied subjects. We found higher sensitivity than specificity and higher positive predictive value than negative predictive value for FVC/FENO, FEV1/FENO, and FEF25-75%/FENO and found a mirror image for reverse parameters. However, the positive predictive values and negative predictive values were not clearly convincing with respect to diagnostic accuracy in the case of the new parameters proposed.
  
  
  CONCLUSIONS
  We propose new lung function/lung inflammation ratios by which it may become possible to diagnose asthma in children and adolescents on the basis of a subject's spirometry and FENO measurements. We believe that our ratios are only supportive of the universally used parameters in the process of diagnosing asthma. (ClinicalTrials.gov registration NCT01805635.).
authors.affiliation: Departments of Pediatrics and Allergy, N. Copernicus Hospital, Medical University of Lodz, Lodz, Poland. Atlantic Clinic LTD, Southampton, Hampshire, United Kingdom.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Grzelewski
authors.affiliation: Department of Social and Preventive Medicine, Medical University of Lodz, Lodz, Poland.
authors.forename: Włodzimierz
authors.initials: W
authors.lastname: Stelmach
authors.affiliation: Institute of Dental Surgery, Faculty of Medicine and Dentistry, Medical University of Lodz, Lodz, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Stelmach
authors.affiliation: Institute of Dental Surgery, Faculty of Medicine and Dentistry, Medical University of Lodz, Lodz, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Janas
authors.affiliation: Faculty of Nursing and Midwifery, Division of Nursing, Medical University of Lodz, Lodz, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Grzelewska
authors.affiliation: family doctor, private practice, Kon-Med, Lodz, Poland.
authors.forename: Konrad
authors.initials: K
authors.lastname: Witkowski
authors.affiliation: Department of Laboratory Diagnostics, N. Barlicki Hospital, Medical University of Lodz, Lodz, Poland.
authors.forename: Eusebio
authors.initials: E
authors.lastname: Makandjou-Ola
authors.affiliation: Department of Internal Medicine, Asthma and Allergy, Medical University of Lodz, Lodz, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Majak
authors.affiliation: Departments of Pediatrics and Allergy, N. Copernicus Hospital, Medical University of Lodz, Lodz, Poland. alergol@kopernik.lodz.pl.
authors.forename: Iwona
authors.initials: I
authors.lastname: Stelmach
mesh_terms: D000293:Adolescent; D000403:Airway Resistance; D001249:Asthma / Q000175:diagnosis*; D001944:Breath Tests / Q000379:methods; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D045853:Exhalation; D005260:Female; D005540:Forced Expiratory Flow Rates; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013147:Spirometry / Q000379:methods*; D014797:Vital Capacity; D055815:Young Adult
chemical_list: D009569:Nitric Oxide
keywords: asthma diagnosis; children; nitric oxide; respiratory function; young adults