8.1 Introduction
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8.1.1 Metered dose inhalers
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Chronic obstructive pulmonary disease (COPD)
COPD is a condition involving the narrowing and inflammation of the airways in conjunction with damage to the lung tissue (emphysema). COPD is caused primarily by cigarette smoking, with inhalation of occupational dusts or environmental air pollution as potential co-factors. COPD is persistent and progressive if the patient continues to smoke, and further deterioration can still occur even after smoking cessation. COPD ultimately leads to permanent disability and death. Acute exacerbations of COPD frequently require hospitalization.
The prevalence of COPD in many developed countries is around 4–17 percent in the adult population aged over 40 years (summarized in Celli et al., 1999). Data are less certain in developing countries but figures as high as 26 percent have been quoted. Rates in men are generally higher than women and reflect smoking prevalence. Smoking is beginning to decline in some developed countries, but trends in developing countries indicate that both smoking and the prevalence of COPD are of increasing concern. In the 1996 Global Burden of Disease Study sponsored by the World Health Organization, COPD was ranked 12 in terms of disability, but is projected to rank 5 in 2020, behind ischaemic heart disease, major depression, traffic accidents and cerebrovascular disease.
In 1998, COPD was the fourth most common cause of death in the United States after heart disease, cancer and stroke. In most developed countries, the male death rate from COPD has been declining. By contrast, the female mortality rate is increasing and it is expected that mortality rates amongst females will overtake those men by about 2005.
