title: Argument for changing criteria for bronchodilator responsiveness.
abstract: BACKGROUND
  Extensively used current guidelines of the American Thoracic Society/European Respiratory Society (ATS/ERS) define a positive aerosolized bronchodilator (BD) response as: "...an increase in FEV(1) and/or FVC > or = 12% of control and > or = 200 mL." We hypothesized that BD responsiveness was better assessed using a statistical approach, linked to each individual's spirometric measurements, rather than the variability of others.
  
  
  METHODS
  We retrospectively analyzed 1-year's pre- and post-BD spirometric tests from our hospital's clinical laboratory. Using measurements of forced expiratory volume in 1-s (FEV(1)), forced expiratory volume in 3-s (FEV(3)), and forced vital capacity (FVC) from each of three satisfactory forced pre-BD and three satisfactory forced post-BD spirometric maneuvers, we classified each of 313 consecutive patient studies as responders or non-responders in two ways. First, we used ATS/ERS guideline criteria based on population variability. Second, we used unpaired, single-tailed t-tests at P<0.05 for FEV(1), FEV(3), and FVC, considering the variability of and difference between each individual's pre- and post-BD maneuvers.
  
  
  RESULTS
  135 studies were both ATS/ERS and t-test non-responders, three were ATS/ERS responders and t-test non-responders, 86 were ATS/ERS and t-test responders, and 89 were ATS/ERS non-responders and t-test responders. The latter 89 included many patients with either low baseline FEV(1) (< 1.50 L) who could not reach the 200 mL increase criterion or high baseline FEV(1) (> 3.00 L) who could not reach the 12% increase criterion.
  
  
  CONCLUSIONS
  We believe individual t-tests may categorize patient's BD responsiveness better than ATS/ERS guideline criteria which are based on population responses and require both fixed volume and percentage changes. Its usefulness by others remains to be shown.
authors.affiliation: Division of Respiratory and Critical Care Physiology and Medicine, Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA. jhansen@labiomed.org
authors.forename: James E
authors.initials: JE
authors.lastname: Hansen
authors.forename: Xing Guo
authors.initials: XG
authors.lastname: Sun
authors.forename: David
authors.initials: D
authors.lastname: Adame
authors.forename: Karlman
authors.initials: K
authors.lastname: Wasserman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001993:Bronchodilator Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003627:Data Interpretation, Statistical; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012140:Respiratory Tract Diseases / Q000188:drug therapy* / Q000503:physiopathology; D012189:Retrospective Studies; D013147:Spirometry; D016896:Treatment Outcome; D014797:Vital Capacity / Q000187:drug effects*; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents