title: Poor symptom control is associated with reduced CT scan segmental airway lumen area in smokers with asthma.
abstract: BACKGROUND
  Cigarette smoking is associated with worse symptoms in asthma and abnormal segmental airways in healthy subjects. We tested the hypothesis that current symptom control in smokers with asthma is associated with altered segmental airway dimensions measured by CT scan.
  
  
  METHODS
  In 93 subjects with mild, moderate, and severe asthma (smokers and never smokers), we recorded Asthma Control Questionnaire-6 (ACQ-6) score, spirometry (FEV1; forced expiratory flow rate, midexpiratory phase [FEF(25%-75%)]), residual volume (RV), total lung capacity (TLC), and CT scan measures of the right bronchial (RB) and left bronchial (LB) segmental airway dimensions (wall thickness, mm; lumen area, mm²) in the RB3/LB3, RB6/LB6, and RB10/LB10 (smaller) airways.
  
  
  RESULTS
  The CT scan segmental airway (RB10 and LB10) lumen area was reduced in smokers with asthma compared with never smokers with asthma; RB10, 16.6 mm² (interquartile range, 12.4-19.2 mm²) vs 19.6 mm² (14.7-24.2 mm²) (P = .01); LB10, 14.8 mm² (12.1-19.0 mm²) vs 19.9 mm² (14.5-25.0 mm²) (P = .003), particularly in severe disease, with no differences in wall thickness or in larger airway (RB3 and LB3) dimensions. In smokers with asthma, a reduced lumen area in fifth-generation airways (RB10 or LB10) was associated with poor symptom control (higher ACQ-6 score) (-0.463 [-0.666 to -0.196], P = .001, and -0.401 [-0.619 to -0.126], P = .007, respectively) and reduced postbronchodilator FEF(25%-75%) (0.521 [0.292-0.694], P < .001, and [0.471 [0.236-0.654], P = .001, respectively) and higher RV/TLC %.
  
  
  CONCLUSIONS
  The CT scan segmental airway lumen area is reduced in smokers with asthma compared with never smokers with asthma, particularly in severe disease, and is associated with worse current symptom control and small airway dysfunction.
authors.affiliation: Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow. Electronic address: neil.thomson@glasgow.ac.uk.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Thomson
authors.affiliation: Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow.
authors.forename: Rekha
authors.initials: R
authors.lastname: Chaudhuri
authors.affiliation: Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow.
authors.forename: Mark
authors.initials: M
authors.lastname: Spears
authors.affiliation: Robertson Centre for Biostatistics, University of Glasgow, Glasgow.
authors.forename: Claudia-Martina
authors.initials: CM
authors.lastname: Messow
authors.affiliation: UoE/MRC Centre for Inflammation Research, Medical Physics and Clinical Radiology, University of Edinburgh, Edinburgh.
authors.forename: William
authors.initials: W
authors.lastname: MacNee
authors.affiliation: UoE/MRC Centre for Inflammation Research, Medical Physics and Clinical Radiology, University of Edinburgh, Edinburgh.
authors.forename: Martin
authors.initials: M
authors.lastname: Connell
authors.affiliation: UoE/MRC Centre for Inflammation Research, Medical Physics and Clinical Radiology, University of Edinburgh, Edinburgh.
authors.forename: John T
authors.initials: JT
authors.lastname: Murchison
authors.affiliation: Department of Radiology, Gartnavel General Hospital, Glasgow, Scotland.
authors.forename: Michael
authors.initials: M
authors.lastname: Sproule
authors.affiliation: Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow.
authors.forename: Charles
authors.initials: C
authors.lastname: McSharry
mesh_terms: D000328:Adult; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects*; D013147:Spirometry; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D018927:Anti-Asthmatic Agents