Predicting Response to Bronchodilator Therapy in Chronic Obstructive Pulmonary Disease

Although the diagnosis and assessment of airflow obstruction is accomplished by pulmonary function test measurements (PFTs),¹it has recently become clear that comparing PFTs before and after bronchodilator (BD) is of limited value either to (1) separate chronic obstructive pulmonary diseases (COPD) from asthma²or (2) predict the long-term clinical response of patients with COPD to BD therapy.³The article by Guyatt et al⁴in this issue of the Archives adds to the growing evidence that PFTs before and after BD are indeed imperfect guides to predicting clinical response to BD therapy in COPD. We will review the potential reasons that may explain this finding. See also p 1949. Traditionally, the mainstay of therapy in COPD has been the use of pharmacologic agents directed at improving the basic physiologic abnormality of chronic airflow obstruction.⁵The principal BDs used have been a variety of inhaled sympathomimetic