Inhaled corticosteroids: a controversial add-on treatment in COPD.

We would like to thank J.E. Hansen for his detailed response to our recently published analysis regarding prevalence of bronchoreversibility in subjects enrolled in the National Emphysema Treatment Trial [1]. J.E. Hansen raises a concern that the American Thoracic Society (ATS)/European Respiratory Society (ERS) definition of bronchoreversibility is too restrictive in that it requires both an absolute forced expiratory volume in 1 s (FEV1) o200 mL and a 12% increase in FEV1 to qualify as a positive test, which may underestimate bronchoreversibility in a patient population with very low lung function. J.E. Hansen has asked us for a reanalysis of the data with this in mind. If we use the ATS criteria for bronchoreversibility, 121 (22.2%) subjects met these criteria at least once during the period of evaluation. If we choose a 12% absolute increase in FEV1 alone as our definition for bronchoreversibility, 452 (83%) subjects met this criterion at least once during the period of evaluation. As J.E. Hansen suspected, the number of subjects meeting this less restrictive criterion is significantly higher, although possibly too high, making the clinical utility less clear. As J.E. Hansen pointed out, identifying the ‘‘perfect’’ measure for bronchoreversibility is not an easy task and perhaps should depend on the subject population being studied. The data we present in our paper helps us to better understand the prevalence of bronchoreversibility in the severe emphysema patient population, but the choice of definition for bronchoreversibility should ultimately be determined by the definition that best discriminates patients as they relate to clinically meaningful outcomes.