Chest
Volume 118, Issue 4, October 2000, Pages 981-989
Journal home page for Chest

Clinical Investigations
COPD
Geographic Variations in Prevalence and Underdiagnosis of COPD: Results of the IBERPOC Multicentre Epidemiological Study

https://doi.org/10.1378/chest.118.4.981Get rights and content

Objectives:

To ascertain the prevalence, diagnostic level, and treatment of COPD in Spain through a multicenterstudy comprising seven different geographic are as.

Designand participants:

This is an epidemiologic, multicenter, population-based study conducted in seven are as of Spain. A total of4,035 men and women (age range, 40 to 69 years) who were randomlyselected from a target population of 236,412 subjects participated inthe study.

Interventions:

Eligible subjects answeredthe European Commission for Steel and Coal questionnaire. Spirometrywas performed, followed by a bronchodilator test when bronchialobstruction was present.

Results:

The prevalence of COPD was 9.1% (95% confidence interval [CI], 8.1 to 10.2%), 15%in smokers (95% CI, 12.8 to 17.1%), 12.8% in ex-smokers (95% CI,10.7 to 14.8%), and 4.1% in nonsmokers (95% CI, 3.3 to 5.1%). Theprevalence in men was 14.3% (95% CI, 12.8 to 15.9%) and 3.9% inwomen (95% CI, 3.1 to 4.8%). Marked differences were observed betweensexes in smoking; the percentage of nonsmokers was 23% in men and76.3% in women (p < 0.0001). The prevalence of COPD varied amongthe areas, ranging from 4.9% (95% CI, 3.2 to 7.0%) in the area of the lowest prevalence to 18% (95% CI, 14.8 to 21.2%) in the area of the highest. There was no previous diagnosis of COPD in 78.2% of cases(284 of 363). Only 49.3% of patients with severe COPD, 11.8% of patients with moderate COPD, and 10% of patients with mild COPD werereceiving some kind of treatment for COPD. Multivariate analysis showedthat individuals had a higher probability of having received a previousdiagnosis of COPD if they lived in urban areas, were of male gender, were > 60 years old, had higher educational levels, had > 15pack-year smoking history, or had symptoms of chronicbronchitis.

Conclusions:

COPD is a veryfrequent disease in Spain, and presents significant geographicvariations and a very low level of previous diagnosis and treatment, even in the most advanced cases.

Section snippets

Design of the Study

This is an epidemiologic, multicenter, population-based studyconducted in seven areas of Spain. The areas included in the study wererepresentative of different climates and comprised urban and ruralpopulations (Fig 1). The description of these areas is shown in Table 1.

Selection of Participants

The total target population consisted of 236,412 subjectsincluded in the administrative census and residing in the seven studyareas. From these, a randomized, age- and sex-stratified sample of5,014 individuals (2,592 women and

Participation and Distribution of the Study Population

The detailed description of participation rates in the study, bothglobal and in different areas, has been publishedrecently.21 In brief, to achieve the aim of 5,014interviews, a total of 5,827 attempts at contact were made, of which860 subjects (14.8%) did not respond and were replaced; 918 subjects(18%) refused to participate, although 882 of these subjects (94.6%)agreed to answer the short questionnaire by telephone. In all, 4,035complete interviews were achieved, which represent 69.2% of the

Discussion

Our results reveal a great variation in the prevalence of COPDamong the different areas studied, with a global prevalence of 9.1%,oscillating between 4.9% and 18%, an evident predominance in men, anda low level of previous diagnosis and treatment.

In this study, we attempted to avoid possible biases derived from ourpopulation sample and the methodology. First, the sample was chosenusing a random sample from of ficial censuses of the populationsstudied, stratified by age groups and sex. Although

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