Acute bronchodilator responsiveness in subjects with and without airflow obstruction in five Latin American cities: the PLATINO study.
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 FEV(1)/FVC<0.70). In this analysis, subjects with pre-bronchodilator FEV(1)/FVC <0.70 but > or =0.70 post-bronchodilator were considered to have reversible obstruction. Bronchodilator responsiveness after albuterol 200microg was assessed using three definitions: a) FVC and/or FEV(1) increment > or =12% plus > or =200mL over baseline; b) FEV(1)> or =15% increase over baseline; and c) FEV(1) increase > or =10% of predicted value.


RESULTS
There were 756 healthy respiratory subjects, 481 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. FEV(1) changes were lower (110.6+/-7.40 vs. 164.7+/-11.8mL) and FVC higher (146.5+/-14.2mL vs. -131.0+/-19.6mL) in COPD subjects compared with reversible obstructed. Substantial overlap in FEV(1) 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 FEV(1) and FVC changes after bronchodilator among the groups makes it difficult to determine a threshold for separating them.
Montes de Oca
Maria
M
Servicio de Neumonología, Hospital Universitario de Caracas, Facultad de Medicina, Los Chaguaramos, 1030, Universidad Central de Venezuela, Caracas, Venezuela. mmdeoca@cantv.net
Perez-Padilla
Rogelio
R
Tálamo
Carlos
C
Halbert
Ronald J
RJ
Moreno
Dolores
D
Lopez
Maria Victorina
MV
Muiño
Adriana
A
José Roberto
B Jardim
BJ
Valdivia
Gonzalo
G
Pertuzé
Julio
J
Ana Maria
B Menezes
BM
D000368:Aged; D001980:Bronchi / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*