title: Chronic obstructive pulmonary disease prevalence in Lisbon, Portugal: the burden of obstructive lung disease study.
abstract: BACKGROUND
  There is a great heterogeneity in the prevalence of Chronic Obstructive Pulmonary Disease (COPD) demonstrates a great heterogeneity across the world. The Burden of Obstructive Lung Disease (BOLD) initiative was started to measure the prevalence of COPD in a standardized way. We aimed to estimate the prevalence of COPD in Portuguese adults aged 40 years or older of a target population of 2,700 000 in the Lisbon region, in accordance with BOLD protocol.
  
  
  METHODS
  A stratified, multi-stage random sampling procedure was used which included 12 districts. The survey included a questionnaire with information on risk factors for COPD and reported respiratory disease and a post-bronchodilator spirometry performed at survey centres.
  
  
  RESULTS
  For the 710 participants with questionnaires and acceptable spirometry, the overall weighted prevalence of GOLD stage I+ COPD was 14.2% (95% C.I. 11.1, 18.1), and stage II+ was 7.3% (95% C.I. 4.7, 11.3). Unweighted prevalence was 20.2% (95% C.I.17.4, 23.3) for stage I+ and 9.5% (95% C.I. 7.6, 11.9) for stage II+. Prevalence of COPD in GOLD stage II+ increased with age and was higher in men. The prevalence of GOLD stage I+ COPD was 9.2% (95% C.I. 5.9, 14.0) in never smokers versus 27.4% (95% C.I. 18.5, 38.5) in those who had smoked >20 pack-years. The agreement between previous doctor diagnosis and spirometric diagnosis was low, with 86.8% of underdiagnosed individuals.
  
  
  CONCLUSIONS
  The 14.2% of COPD estimated prevalence indicates that COPD is a common disease in the Lisbon region. In addition, a large proportion of underdiagnosed disease was detected. The high prevalence of COPD with a high level of underdiagnosis, points to the need of raising awareness of COPD among health professionals, and requires more use of spirometry in the primary care setting.
authors.affiliation: Advisory Board do Projeto Burden of Obstructive Lung Disease-Portugal, Sociedade Portuguesa de Pneumologia, Portugal. cristina.barbara@chln.min-saude.pt
authors.forename: C
authors.initials: C
authors.lastname: Bárbara
authors.forename: F
authors.initials: F
authors.lastname: Rodrigues
authors.forename: H
authors.initials: H
authors.lastname: Dias
authors.forename: J
authors.initials: J
authors.lastname: Cardoso
authors.forename: J
authors.initials: J
authors.lastname: Almeida
authors.forename: M J
authors.initials: MJ
authors.lastname: Matos
authors.forename: P
authors.initials: P
authors.lastname: Simão
authors.forename: M
authors.initials: M
authors.lastname: Santos
authors.forename: J R
authors.initials: JR
authors.lastname: Ferreira
authors.forename: M
authors.initials: M
authors.lastname: Gaspar
authors.forename: L
authors.initials: L
authors.lastname: Gnatiuc
authors.forename: P
authors.initials: P
authors.lastname: Burney
mesh_terms: D000328:Adult; D000368:Aged; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology*; D013147:Spirometry; D011795:Surveys and Questionnaires