Chronic obstructive pulmonary disease (COPD) is an increasingly important public health problem. It remains one of the leading causes of disability in developed countries and is projected to be the fourth leading cause of death worldwide in 2020.⁶¹ The costs of medical care for these patients are enormous and long-term outcomes are poor.²¹ Bronchodilators, antibiotics, immunizations, smoking cessation, exercise and long-term oxygen cause measurable improvements in clinical outcomes, but the magnitudes of the effects are generally modest.

Over the past 20 years, corticosteroids, both oral and inhaled, have assumed a prominent role in the treatment of COPD. In some clinical settings, nearly one half of patients with COPD receive inhaled corticosteroids, and this number represents a substantial increase from a few years previously.^{42, 59 and 90} Many physicians now view systemic corticosteroids as standard therapy for severe COPD exacerbations, a practice that was not true a generation ago.⁵⁹ A small proportion of patients with COPD, approximately 4 % to 10 % , take systemic corticosteroids repeatedly or continuously and are labeled as steroid-dependent.^{42 and 59}

Adoption of these clinical practice patterns was not evidence based. Practice patterns evolved without compelling data that corticosteroids, in any form, improve clinical outcomes in COPD. The rationale for using both inhaled and oral corticosteroids in COPD is partly a result of their well-established effectiveness in the treatment of asthma.^{40 and 75} Historically, physicians have tended to transfer proven therapies from asthma to COPD, and this transfer may be because of the diagnostic confusion that frequently exists between these two conditions in older patients. In addition, pathophysiologic studies of patients with COPD have demonstrated a low-grade inflammatory reaction in the airways that may lead to occlusive, fibrotic changes over many years.⁶³ Chronic inflammation has also been implicated in the pathogenesis of emphysema.⁶² Suppression of these inflammatory responses provides a rationale for using corticosteroids.

The question of efficacy is important, however, because corticosteroids may cause major adverse effects, particularly when given systemically. Several large clinical trials have recently been completed or are nearing completion and they should provide better evidence for making informed clinical decisions about the use of both inhaled and systemic corticosteroids in COPD. Analyses and publication of these trials are as yet incomplete, and in the meantime the clinician must evaluate whether the benefits of such therapy outweigh the potential for adverse events. This evaluation is particularly pertinent in the population of patients with COPD, who generally are older, less active, and have significant tobacco use histories, all of which may place them at greater risk for adverse effects.