Acute bronchodilator responsiveness in subjects with and without airflow obstruction in five Latin American cities: The PLATINO study

Abstract

Background: Acute bronchodilator responsiveness is an area of discussion in COPD. No information exists regarding this aspect of the disease from an unselected COPD population. We assessed acute bronchodilator responsiveness and factors influencing it in subjects with and without airway obstruction in an epidemiologic sample.

Methods: COPD was defined by GOLD criteria (post-bronchodilator FEV1/FVC <0.70). In this analysis, subjects with pre-bronchodilator FEV1/FVC <0.70 but >= 0.70 post-bronchodilator were considered to have reversible obstruction. Bronchodilator responsiveness after albuterol 200 mu g was assessed using three definitions: a) FVC and/or FEV1 increment >= 12% plus >= 200 mL over baseline; b) FEV1 >= 15% increase over baseline; and c) FEV1 increase >= 10% of predicted value.

Results: There were 756 healthy respiratory subjects, 48 1 subjects with reversible obstruction and 759 COPD subjects. Depending on the criterion used the proportion of person with acute bronchodilator responsiveness ranged between 15.0-28.2% in COPD, 11.4-21.6% in reversible obstructed and 2.7-7.2% in respiratory healthy. FEV1 changes were lower (110.6 +/- 7.40 vs. 164.7 +/- 11.8 mL) and FVC higher (146.5 +/- 14.2 mL vs. -131.0 +/- 19.6 mL) in COPD subjects compared with reversible obstructed. Substantial overlap in FEV1 and FVC changes was observed among the groups. Acute bronchodilator responsiveness in COPD persons was associated with less obstruction and never smoking.

Conclusions: Over two-thirds of persons with COPD did not demonstrate acute bronchodilator responsiveness. The overall response was small and less than that considered as significant by ATS criteria. The overlap in FEV1, and FVC changes after bronchodilator among the groups makes it difficult to determine a threshold for separating them. (C) 2009 Elsevier Ltd. All rights reserved.