Figure 1.

A schematic adaptation of FEV₁/age graph in susceptible smokers with COPD. The progressive decline in FEV₁ is associated with increased tendency for lung exacerbations. The ECLIPSE study² found that a group of patients can have exacerbations at higher level of FEV₁. The dashed blue lines are the level of FEV₁ at which each set of symptoms/complication of COPD are broadly occur. FEV₁: forced expiratory volume in 1 second; COPD: chronic obstructive pulmonary disease.