title: Total specific airway resistance vs spirometry in asthma evaluation in children in a large real-life population.
abstract: BACKGROUND
  Total specific airway resistance (sRtot) has been introduced as an alternative technique to assess lung function with a particular application to younger children with asthma.
  
  
  OBJECTIVE
  To establish a diagnostic value of the body plethysmographic parameter (sRtot) in asthma diagnosis in young children.
  
  
  METHODS
  This was a prospective, noninterventional study. Children 4 to 18 year old with symptoms suggestive of asthma were included (n = 885). Subjects underwent body plethysmography and spirometry (when capable) with reversibility tests. Of 788 subjects who could perform spirometry in addition to body plethysmography, 578 were diagnosed with asthma. Subjects with asthma were treated for minimum of 6 months and then their asthma was confirmed or refuted.
  
  
  RESULTS
  In 471 patients, asthma diagnosis was confirmed after 6 months of antiasthmatic treatment; 142 patients were 4 to 6 years old and 329 were 7 to 18 years old. Change in response to bronchodilator in children with asthma was significant for sRtot (P = .02) but not for forced expiration volume in 1 second (P = .21); sRtot was more sensitive and specific in identifying children with reversible obstruction than spirometry. There was a significant association between sRtot and asthma diagnosis in patients 4 to 6 years old (odds ratio 1.02, 95% confidence interval 1.01-1.03, P = .001); to differentiate subjects with asthma from those without asthma, the optimal cutoff point for sRtot was 174.5%. A sRtot value higher than 174.5% was associated with a positive prediction of an asthma diagnosis in patients 4 to 6 years old. A ratio of forced expiration volume in 1 second to forced vital capacity below 80% was not significantly associated with asthma.
  
  
  CONCLUSIONS
  These data support the recommendation of performing sRtot rather than spirometry in young children as a fairly sensitive marker of asthma.
  
  
  BACKGROUND
  www.ClinicalTrials.gov (NCT01805635).
authors.affiliation: Department of Pediatrics and Allergy, Medical University of Lodz, Copernicus Memorial Hospital, Lodz, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Jerzyńska
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: Department of Pediatrics and Allergy, Medical University of Lodz, Copernicus Memorial Hospital, Lodz, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Galica
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: Department of Pediatrics and Allergy, Medical University of Lodz, Copernicus Memorial Hospital, Lodz, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Woicka-Kolejwa
authors.affiliation: Department of Pediatrics and Allergy, Medical University of Lodz, Copernicus Memorial Hospital, Lodz, Poland. Electronic address: alergol@kopernik.lodz.pl.
authors.forename: Iwona
authors.initials: I
authors.lastname: Stelmach
mesh_terms: D000293:Adolescent; D000403:Airway Resistance / Q000502:physiology*; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D010991:Plethysmography / Q000379:methods*; D011446:Prospective Studies; D013147:Spirometry / Q000379:methods*
chemical_list: D001993:Bronchodilator Agents