ABSTRACT
Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality in the U.S. As many as 16 million Americans have symptomatic COPD; it is the fourth most common cause of death in the U.S. and results in direct medical costs of $15 billion in the U.S. alone. It is the only one among the top 10 causes of death with a continuing increase in morbidity and mortality.1 The diagnosis of chronic obstructive pulmonary disease is based on the presence of clinical symptoms such as chronic cough with sputum production and objective information measured in the lung function test to confirm the diagnosis and classify the disease.2
