Table 1: Main differences between COPD and Asthma.


OnsetMid lifeEarly or Late onset
Risk factorsSmokingAtopy, irritant exposures, smoking
SymptomsSlowly progressiveIntermittent
(i) Breathlessness On moderate/minimal effortOn exacerbations
(ii) Cough RegularlyOn exacerbations
Family historyMay be presentMay be present
FEV1/FVC ratio<70%<70%
FEV1% predicted<80%<80%
Bronchodilator responseAbsent/presentPresent
Inflammatory cellsNeutrophilsEosinophils
CD8+ cells (Tc)Mast cells
CD4+ cells (Th2)
Structural changesAirway smooth muscle +Airway smooth muscle +++
Peripheral airwaysAll airways
Parenchymal destructionNo parenchymal involvement
Epithelial metaplasiaEpithelial shedding
Fibrosis++ (peribronchiolar)Fibrosis + (subepithelial)
Mucus secretion +++Mucus secretion +
Steroid response+/−+++