title: Practical surrogate marker of pulmonary dysanapsis by simple spirometry: an observational case-control study in primary care.
abstract: BACKGROUND
  We see patients who present with spirometry airflow limitation despite their forced expiratory volume in one second (FEV1) as well as forced vital capacity (FVC) to be supernormal (FEV1/FVC < 70%, both the %FEV1 and the %FVC ≧ 100%) in asymptomatic healthy non-smokers. Based on previous studies, we hypothesized these spirometry conditions (results measured with spirometry) could be suitably used as a practical surrogate marker of pulmonary dysanapsis: the condition of disproportionate but physiologically normal growth between airways and lung parenchyma.
  
  
  METHODS
  We compared the conventional surrogate marker of dysanapsis, maximum mid-expiratory flow to FVC (MMF/FVC), in SUBJECTS (FEV1/FVC < 70%, both the %FEV1 and the %FVC ≧ 100% in healthy non-smokers) (n = 25), in EMPHYSEMA (CT confirmed pulmonary emphysema, same spirometry results with SUBJECTS) (n = 55), and in CONTROLS (age- and height- matched, normal spirometry results) (n = 25). Next we added imaging analysis to evaluate the relationship between the cross sectional airway luminal area (X-Ai) and the lung volume results among the three groups.
  
  
  RESULTS
  The MMF/FVC was significantly lower in SUBJECTS and in EMPHYSEMA compared to CONTROLS. However, percent predicted peak expiratory flow (%PEFR) was significantly lower only in SUBJECTS and not in EMPHYSEMA compared to CONTROLS. The ratio of the X-Ai of the trachea and right apical bronchus to lung volume was significantly lower in SUBJECTS compared to CONTROLS.
  
  
  CONCLUSIONS
  The simple spirometry conditions in SUBJECTS are highly suggestive of practical surrogate marker of pulmonary dysanapsis. Awareness of this concept would help to attenuate the risk of overdiagnosis of obstructive pulmonary disease.
authors.affiliation: Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, 113-8421, Bunkyo-ku, Tokyo, Japan. sshiota@jutendo.ac.jp.
authors.forename: Satomi
authors.initials: S
authors.lastname: Shiota
authors.affiliation: Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, 113-8421, Bunkyo-ku, Tokyo, Japan. koara@juntendo.ac.jp.
authors.forename: Masako
authors.initials: M
authors.lastname: Ichikawa
authors.affiliation: Department of Radiology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, 113-8421, Bunkyo-ku, Tokyo, Japan. ka-suzz@juntendo.ac.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, 113-8421, Bunkyo-ku, Tokyo, Japan. yfukuchi@tea.ocn.ne.jp.
authors.forename: Yoshinosuke
authors.initials: Y
authors.lastname: Fukuchi
authors.affiliation: Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, 113-8421, Bunkyo-ku, Tokyo, Japan. kztakaha@juntendo.ac.jp.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000368:Aged; D058070:Asymptomatic Diseases; D016022:Case-Control Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D008297:Male; D011656:Pulmonary Emphysema / Q000453:epidemiology; D012189:Retrospective Studies; D013147:Spirometry; D014797:Vital Capacity