Figure 1.

Bronchodilator response rates in subjects with chronic obstructive pulmonary disease at enrollment and follow-up visit. ATS = American Thoracic Society; ATS-BDR = increase in prebronchodilator FEV₁ and/or FVC ≥12% and ≥200 ml after bronchodilator administration; BDR = bronchodilator response; Combined-BDR = an increase in both FEV₁ and FVC ≥12% and ≥200 ml after bronchodilator administration; COPD = chronic obstructive pulmonary disease; FEV₁ = forced expiratory volume in 1 second; FVC = forced vital capacity; FEV₁-BDR = increase in FEV₁ ≥12% and ≥200 ml but a change in FVC <12% and 200 ml after bronchodilator administration; FVC-BDR = increase in FVC ≥12% and ≥200 ml but a change in FEV₁ <12% and 200 ml after bronchodilator administration; No-BDR = a change in both FEV₁ and FVC <12% and <200 ml after bronchodilator administration.