The left panel shows 5-year mortality rates of patients classified by pulmonary function test according to the ATS guidelines: Stage I, FEV₁ > 50% of predicted; Stage II FEV₁ = 35 to 49% of predicted; and Stage III, FEV < 35% of predicted. The right panel shows 5-year mortality of patients classified by dyspnea grade as measured with the Medical Research Council Breathlessness Scale (MRC): Grade II (short of breath when hurrying on the level or walking up a slight hill); Grade III (have to walk slower than most people on the level); Grade IV (have to stop for breath after walking about 100 yards (or after a few minutes) on the level); Grade V (too breathless to leave the house, or breathless after undressing). Data from Nishimura et al [19].