Table 1.

  Canadian Thoracic Society and Canadian Infections Disease Society Chronic Bronchitis (CB) Stratification System ³

Category of CB	Clinical Characteristics
Group 0 (acute tracheobronchitis)	Cough and sputum without previous pulmonary disease (patients do not meet definition of CB)
Group I (simple CB)	<4 exacerbations/year (meets definition of CB)FEV1>50% predicted
Group II (complicated CB)	FEV1<50% predictedFEV1 50–65% predicted and significant comorbidity: congestive heart failure, coronary artery disease, or >4 exacerbations/year
Group III (suppurative CB)	As in Group II but with constant purulent sputumFrequent exacerbation (>4/year) may have bronchiectasisFEV1<50% predicted (usually <35% predicted)

FEV₁=forced expiratory volume in 1 second.