Reversing concepts on COPD irreversibility.

" C ommon diseases are complex. The study of complexity is based on a new way of thinking that stands in sharp contrast to the philosophy underlying Newtonian science, which is based on reductionism, determinism and objective knowledge. Initially, we might aim to reduce complexity to understand nature [1]. In the current issue of the European Respiratory Journal (ERJ), TASHKIN et al. [2] report the baseline results for bronchial hyperresponsiveness in patients recruited in an ongoing, large chronic obstructive pulmonary disease (COPD) clinical trial, the Understanding the Potential Long-Term Impacts on Function with Tiotropium (UPLIFT) trial [3]. This report [2] challenges the vastly established concept that lung function in COPD is largely irreversible. TASHKIN et al. [2] concluded that over one-half to nearly two-thirds of participating subjects met the most commonly used criteria for acute bronchodilator responsiveness, and more than one-third showed acute responsiveness by an increase in the percentage predicted criterion. Most certainly, the combined strategy employed in the UPLIFT trial involving the use of two bronchodilators (80 mg ipratropium and 400 mg salbutamol) to ensure maximum or near-maximum bronchodilation magnifies this biological finding. Currently, both American Thoracic Society/European Respiratory Society [4] and Global Initiative for Chronic Obstructive Lung Disease [5] COPD guidelines insist that COPD staging is to be performed post-bronchodilation; a previous recommendation of 400 mg salbutamol [6] seems long forgotten. Both updated documents are vague in recommending what method, dose or treatment to follow. Not surprisingly , the most current asthma guidelines are also vague in recommending which, when and how a bronchodilator test should be administered (200–400 mg salbutamol to produce an increase in forced expiratory volume in one second (FEV1) of .12% and 200 mL from the pre-bronchodilator value, no time specified) [7]. Additionally, to complicate matters further, one could add ''corticosteroid reversibility'' to the mix. Aiming high and because ''the sky is the limit'', some might aim to obtain reference equations of lung function in a super-healthy, nonsymptomatic, never-smoker sample of participants from the general population who are all bronchodilated with a combination of salbutamol, ipratropium and even an inhaled or oral corticosteroid. We don't think this should be the case. The issue of definitions of reversibility of lung function in COPD has been visited in the ERJ [8, 9] and elsewhere before. It is probable that the resources required, should the pattern of bronchodilation used in the UPLIFT trial [3] be implemented …