title: Clinical characteristics of COPD syndrome: A 6-year follow-up study of adult smokers.
abstract: BACKGROUND
  There is little quantitative information about the development of chronic obstructive pulmonary disease (COPD) among adult smokers and of what happens to patients who have already developed COPD.
  
  
  OBJECTIVE
  To examine the development and performance of COPD status over time, and the clinical characteristics of new COPD cases according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2007 and 2011 classifications.
  
  
  METHODS
  Healthy asymptomatic smokers were recruited through newspaper announcements. They filled in questionnaires and had an individualized assessment of their health history during all three visits (visit 1, visit 2 after three years, visit 3 after six years).
  
  
  RESULTS
  Of the eligible 621 heavy smokers, 572 attended visit 2. A total of 513 subjects completed the 6-year follow-up examination. According to GOLD 2007, COPD was present in 22.8% (n = 117) of these smokers. The severity of COPD changed during the years of follow-up. Furthermore, health status and prevalence of chronic respiratory symptoms both in the smokers with normal lung function and in the COPD groups varied over the time period.
  
  
  CONCLUSIONS
  GOLD 2011 recognized the complex patient subgroups better than GOLD 2007. Variability in chronic symptoms or in health status correlated poorly with the severity of airway limitation.
authors.affiliation: a Department of Pulmonary Medicine , Lapland Central Hospital , Rovaniemi , Finland.
authors.forename: Tuula
authors.initials: T
authors.lastname: Toljamo
authors.forename: Anna
authors.initials: A
authors.lastname: Hamari
authors.forename: Marjo
authors.initials: M
authors.lastname: Sotkasiira
authors.forename: Pentti
authors.initials: P
authors.lastname: Nieminen
mesh_terms: D000368:Aged; D001993:Bronchodilator Agents; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology*; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects*; D013147:Spirometry; D013997:Time Factors; D014797:Vital Capacity
chemical_list: D001993:Bronchodilator Agents
keywords: Adult; chronic obstructive pulmonary disease; disease classification; spirometry