Chronic Obstructive Pulmonary Disease Prevalence in Lisbon, Portugal: The Burden of Obstructive Lung Disease Study

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. (C) 2011 Sociedade Portuguesa de Pneumologia. Published by Elsevier Espana, S.L. All rights reserved.