Table 1

Enrolment strata by dyspnoea and lung function

Group 1Group 2Group 3Group 4
Asymptomatic smokersSymptomatic smokersAsymptomatic mild COPDSymptomatic mild COPD
Smoking status>10 pack-years>10 pack-years>10 pack-years>10 pack-years
Dyspnoea mMRC score0≥10≥1
Lung function assessmentPostbronchodilatorPostbronchodilatorPostbronchodilatorPostbronchodilator
FEV1/FVC ratio criteriaFEV1/FVC≥0.7FEV1/FVC ≥0.7FEV1/FVC<0.7FEV1/FVC<0.7
Other spirometric criteriaFVC >80% predFVC >80% predFEV1>80% predFEV1>80% pred
Sample sizen=120n=120
Sample size by groups (approximate)≈50%≈50%≈50%≈50%
  • For simplicity, we have excluded from this schema the Global Initiative for Chronic Obstructive Lung Disease unclassified group.

  • COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; LLN, lower limit of normal; mMRC, modified Medial Research Council dyspnoea score.