ABSTRACT
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in
the United States and the only major cause of death for which the age-adjusted
mortality is increasing (1). This fact has lead some to estimate that COPD will become
the third leading cause of death and fifth leading cause of disability worldwide by the
year 2020 (2). COPD causes significant amount of burden to patients and their family
caregivers as well as to the medical care system (3). There have been no new therapies
for patients with COPD that have been proven to reduce mortality since the reports of
a smoking cessation intervention (4) and the use of long-term oxygen therapy for
severely hypoxemic patients (5). In this sense, all other modern therapies for the
treatment of COPD could be considered palliative in that their benefits are derived
largely from improvements in symptoms and functional status (6-8). However, the
magnitude of the treatment effect, averaged across patients, usually approaches those
considered to be the minimally clinically important different on symptoms and
functional status and there are a significant number of individuals who remain
significantly symptomatic despite maximal therapy (6-8).
