Chronic bronchitis and (pulmonary) emphysema are two respiratory disorders with similar patterns of symptoms: shortness of breath (dyspnea), sputum production, coughing and chest tightness. The two disorders also share important aetiological and pathophysiological characteristics (smoking tobacco, inflammation and destruction of lung tissue). For these reasons, chronic bronchitis and emphysema increasingly are combined into the concept of chronic obstructive pulmonary disease: COPD.
Chronic bronchitis is defined in behavioural terms: ‘the presence of cough and sputum production for at least three months in each of two consecutive years’ (GOLD, 2001, p. 7). Emphysema is defined in pathological terms: ‘destruction of the gas-exchanging surfaces of the lung (alveoli)’ (GOLD, 2001, p. 7). Chronic obstructive pulmonary disease is defined as ‘a disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases’ (GOLD, 2001, p. 6; www.goldcopd.com).
The prevalence of physician-diagnosed COPD is about 2% for men and 1.5% for women. Differences in prevalence per country or region are attributable to a large extent to differences in the prevalence of cigarette smoking (see ‘Tobacco use’). Morbidity in terms of hospitalization, physician visits, emergency department visits, is substantial. Socio-economic costs in terms of absenteeism from work, early retirement and medical care are impressive. The quality of life of COPD patients is severely impaired (Maillé et al., 1996).