The Prevalence of chronic obstructive pulmonary disease among Danes aged 45-84 years: population-based study

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of disability and death in the world. Many people with disease are undiagnosed or untreated due to lack of consensus about the definition of COPD. The objective was to estimate the prevalence of COPD in the Danish population aged 45-84 years and to identify the proportion of persons not receiving appropriate medical treatment. A population-based study in the two Danish counties (population aged 45-84 years = 299,000 persons) based on data from 155 general practices in the 2004-2006 period. Stratified sampling was used to select 4,757 subjects from the Danish Civil Registration System and the National Health Service databases. The diagnosis of COPD was defined as FEV(1)/FVC < 0.70 after bronchodilator. The classification of disease severity was based on criteria developed by the Global Initiative for Chronic Obstructive Lung Diseases (GOLD) criteria. COPD prevalence was associated with sex, age, and smoking status. We found an overall COPD prevalence of 12% (95% CI 11%-13%). Standardized to the Danish population, the true prevalence of COPD is 9% (95% CI 8%-10%). The highest prevalence was observed among current smokers (23%) and former smokers (17%) as well as in the older age group (total = 18%; men = 21%; women = 15%). Most subjects with COPD had mild-to-moderate disease. Among subjects with severe and very severe COPD, 25% were not treated with bronchodilator or inhaled corticosteroids. In conclusion we found that the population prevalence of COPD is high among smokers. A large proportion of persons with COPD did not receive appropriate medical treatment.