Introduction: There is no clear consensus about what constitutes reversibility of airway obstruction. European Respiratory Society (ERS): Increase in FEV1 and/or FVC>12% of their theoretical value and>0.2l. British Thoracic Society: FEV1>15% of initial value and FEV1>0.2l. Global Initiative for Chronic Obstructive Lung Disease: Increase in FEV1>12% and>0.2l. Australia and New Zealand Thoracic Society: Increase in FEV1 >15%. American Thoracic Society/ERS: Increase in FEV1>12% and>0.2l or increase in FVC>12% and 0.2l. Our principal objective was to determine the percentage of patients with COPD (n=62) who were significant responders to the reversibility test according to the 5 recommendations.
Methods: Plethysmography was performed before and 15 minutes after inhalation of 400 micrograms of a short acting bronchodilator (BD). COPD is defined as a FEV1/FVC post BD<0.7.
Results: The percentage of responders varied from 24% to 50% depending on the recommendations used.
Conclusion: Reversibility of airway obstruction is recommendation dependent.