title: Longitudinal changes in airway remodeling and air trapping in severe asthma.
abstract: OBJECTIVE
  Previous cross-sectional studies have demonstrated that airway wall thickness and air trapping are greater in subjects with severe asthma than in those with mild-to-moderate asthma. However, a better understanding of how airway remodeling and lung density change over time is needed. This study aimed to evaluate predictors of airway wall remodeling and change in lung function and lung density over time in severe asthma.
  
  
  METHODS
  Phenotypic characterization and quantitative multidetector-row computed tomography (MDCT) of the chest were performed at baseline and ∼2.6 years later in 38 participants with asthma (severe n = 24 and mild-to-moderate n = 14) and nine normal controls from the Severe Asthma Research Program.
  
  
  RESULTS
  Subjects with severe asthma had a significant decline in postbronchodilator forced expiratory volume in 1 second percent (FEV1%) predicted over time (P < .001). Airway wall thickness measured by MDCT was increased at multiple airway generations in severe asthma compared to mild-to-moderate asthma (wall area percent [WA%]: P < .05) and normals (P < .05) at baseline and year 2. Over time, there was an increase in WA% and wall thickness percent (WT%) in all subjects (P = .030 and .009, respectively) with no change in emphysema-like lung or air trapping. Baseline prebronchodilator FEV1% inversely correlated with WA% and WT% (both P < .05). In a multivariable regression model, baseline WA%, race, and health care utilization were predictors of subsequent airway remodeling.
  
  
  CONCLUSIONS
  Severe asthma subjects have a greater decline in lung function over time than normal subjects or those with mild-to-moderate asthma. MDCT provides a noninvasive measure of airway wall thickness that may predict subsequent airway remodeling.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Witt
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Ajay
authors.initials: A
authors.lastname: Sheshadri
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Luke
authors.initials: L
authors.lastname: Carlstrom
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Jaime
authors.initials: J
authors.lastname: Tarsi
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: James
authors.initials: J
authors.lastname: Kozlowski
authors.affiliation: Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Brad
authors.initials: B
authors.lastname: Wilson
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: David S
authors.initials: DS
authors.lastname: Gierada
authors.affiliation: Department of Radiology, University of Iowa College of Medicine, Iowa City, Iowa.
authors.forename: Eric
authors.initials: E
authors.lastname: Hoffman
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin.
authors.forename: Sean B
authors.initials: SB
authors.lastname: Fain
authors.affiliation: Department of Radiology, University of Iowa College of Medicine, Iowa City, Iowa.
authors.forename: Janice
authors.initials: J
authors.lastname: Cook-Granroth
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Geneline
authors.initials: G
authors.lastname: Sajol
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Oscar
authors.initials: O
authors.lastname: Sierra
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Tusar
authors.initials: T
authors.lastname: Giri
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Neill
authors.affiliation: Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Schechtman
authors.affiliation: Division of Pediatric Allergy, Immunology and Pulmonary Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Bacharier
authors.affiliation: Division of Pulmonary and Critical Care, University of Wisconsin, Madison, Wisconsin.
authors.forename: Nizar
authors.initials: N
authors.lastname: Jarjour
authors.affiliation: Division of Allergy and Immunology, University of Wisconsin, Madison, Wisconsin.
authors.forename: William
authors.initials: W
authors.lastname: Busse
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8052, 660 S. Euclid Ave, St. Louis, MO 63110-1093. Electronic address: castrom@wustl.edu.
authors.forename: Mario
authors.initials: M
authors.lastname: Castro
mesh_terms: D000328:Adult; D056151:Airway Remodeling; D001249:Asthma / Q000150:complications / Q000000981:diagnostic imaging*; D001982:Bronchial Diseases / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D061330:Multidetector Computed Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Severe asthma; airway remodeling; computed tomography