EDITORIAL

Is this the beginning of unravelling the puzzle of COPD exacerbations? R. Rodrı́guez-Roisin T he natural history of chronic obstructive pulmonary disease (COPD) is one of a progressive lung function reduction, essentially expressed by an accelerated decline in forced expiratory volume in one second (FEV1), with limited exercise activity, poor health status and systemic (extrapulmonary) effects, all interspersed with a varying frequency of episodes of COPD exacerbation. Frequency of COPD exacerbations increases with increased disease severity, mostly in patients with advanced COPD (FEV1,50% predicted), who are often prone to frequent and repeated episodes