title: Impact of emphysema and airway wall thickness on quality of life in smoking-related COPD.
abstract: BACKGROUND
  Limited data are available as to the relationship between computed tomography (CT) derived data on emphysema and airway wall thickness, and quality of life in subjects with chronic obstructive pulmonary disease (COPD). Such data may work to clarify the clinical correlate of the CT findings.
  
  
  METHODS
  We included 1778 COPD subjects aged 40-75 years with a smoking history of at least 10 pack-years. They were examined with St George's Respiratory Questionnaire (SGRQ-C) and high-resolution chest CT. Level of emphysema was assessed as percent low-attenuation areas less than -950 Hounsfield units (%LAA). Airway wall thickness was estimated by calculating the square root of wall area of an imaginary airway with an internal perimeter of 10 mm (Pi10).
  
  
  RESULTS
  In both men and women, the mean total score and most of the subscores of SGRQ-C increased with increasing level of emphysema and increasing level of airway wall thickness, after adjusting for age, smoking status, pack years, body mass index and FEV1. The highest gradient was seen in the relationship between the activity score and the emphysema level. The activity score increased by 35% from the lowest to the highest emphysema tertile. The relationship between level of emphysema and the total SGRQ-C score became weaker with increasing GOLD (Global initiative for Chronic Obstructive Lung Disease) stages (p < 0.001), while the impact of gender was limited.
  
  
  CONCLUSIONS
  In subjects with COPD, increasing levels of emphysema and airway wall thickness are independently related to impaired quality of life.
authors.affiliation: Department of Radiology, University of British Columbia, Vancouver General Hospital, 855 12th Ave W, Vancouver, BC V5Z 1M9 Vancouver, BC, Canada. h.gietema@umcutrecht.nl
authors.forename: Hester A
authors.initials: HA
authors.lastname: Gietema
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Edwards
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
authors.forename: Per S
authors.initials: PS
authors.lastname: Bakke
mesh_terms: D000328:Adult; D000368:Aged; D001980:Bronchi / Q000473:pathology*; D001982:Bronchial Diseases / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D011788:Quality of Life; D012907:Smoking / Q000009:adverse effects* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity / Q000502:physiology
keywords: Chronic obstructive pulmonary disease; Computed tomography; Respiratory symptoms; St George respiratory questionnaire