Introduction
Chronic obstructive pulmonary disease (COPD) is a serious
public health problem worldwide. The prevalence, morbidity,
and mortality are expected to rise, especially in countries with
a rapidly aging population and even in populations with reduced smoking rates. A study published by the World
Bank/World Health Organization reported that COPD is
likely to rise from being the twelfth most burdensome disease
in 1990 to the fifth in 2020. This will place an enormous
burden on the healthcare system and will cause a loss in health