TABLE 1

Criteria for early detection of COPD

Criteria	At-risk population [10, 17, 19]	Mild COPD [4, 5]	Early diagnosis of COPD [15]	Early COPD [3]
Symptoms	Cough, dyspnoea, phlegm	Dyspnoea 0–1 mMRC, CAT <10 points	N/A	N/A
Exposure	At least 10 pack-years cigarette smoke or biomass exposure [10, 20]	At least 10 pack-year cigarette smoke or biomass exposure	At least 10 pack-year cigarette smoke	At least 10 pack-year cigarette smoke
Age years	N/A	N/A	N/A	<50
Progression to COPD	∼30–40% [10, 19, 20]	N/A	N/A	Currently in study
Time to COPD diagnosis			5 years
Spirometry
FEV₁/FVC ratio	Normal	<0.7	<0.7	<LLN
FEV₁ decline mL·year⁻¹	Variable [10, 19, 20]	N/A	N/A	>60
FEV₁	Normal	Normal	N/A	N/A
CT scan	>50% CT evidence of emphysema or airway wall thickening [10]	N/A	N/A	Visual emphysema, air trapping or bronchial thickening

FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; CT: computed tomography; mMRC: modified Medical Research Council; CAT: COPD Assessment Test; N/A: not applicable; LLN: lower limit of normal.