The prognostic significance of chronic bronchitis in the development of reversible and irreversible chronic airflow limitation.

This article reviews the potential significance of chronic bronchitis in the development of reversible and irreversible chronic airflow limitation. Because chronic bronchitis is more prevalent than either asthma or chronic obstructive pulmonary disease (COPD), it has the potential to influence the natural history of these two diseases. However, chronic bronchitis does not cause significant obstructive defects in the absence of small airway disease or emphysema and does not significantly contribute to the decline in pulmonary function seen in COPD. In addition, the bronchial hyperreactivity associated with chronic bronchitis has characteristics that clearly distinguish it from asthma. Hence, chronic bronchitis largely reflects cigarette injury to the bronchial mucosa and develops in tandem with emphysema and small airway disease rather than as an essential precursor.