ABSTRACT
The burden of COPD is quite high and its prevalence is increasing. Few data are
available from Latin America. There is no consensus on what criteria should be the
gold standard for the definition of this disease. A population-based study was carried
out in a southern Brazilian city, including adults aged 40–69 years. The aim was to
measure the prevalence of COPD according to several criteria. From the 1,046
subjects chosen from a multiple-stage sampling protocol, a sub-sample of 234 subjects
was systematically selected to undergo spirometry. Percentages of COPD according to
different criteria were: chronic bronchitis by questionnaire (7.8%); GOLD stage 0
(7.3%); fixed ratio (15.2%); GOLD stage II (9.9%); ERS (27.7%). The relationship
among the three lung functional measurements showed that around 70% of all subjects
had negative results with all three criteria, and around 10% were positive according to
all three. Utilization of symptom-based or spirometry definitions of COPD provide
different prevalence estimates. Use of different spirometric criteria also resulted in
different percentages of COPD. According to spirometry, COPD was higher among
men, elderly, those with low education and ex-smokers. On the other hand, current
smokers were more likely to present symptoms of chronic bronchitis. The fixed ratio
criterion is recommended when population-specific reference curves are not available,
while the GOLD definition is recommended to evaluate severity of COPD.