Chronic obstructive pulmonary disease (COPD) is an irreversible lung disease characterized by chronic obstruction of lung airflow that interferes with normal breathing.¹ It affects roughly 14% of the male and 7% of the female population globally,² and it is the third-leading cause of death in the United States.³ The cost of COPD in the United States was projected to be $50 billion in 2010.⁴ Among patients with COPD in the United States, approximately 800,000 receive long-term oxygen therapy (LTOT).⁵ Long-term oxygen therapy has been widely accepted as a means to lower the mortality rate in patients with COPD, particularly in patients with severe hypoxemia.⁶ However, the mortality benefit of this therapy in patients with COPD with mild to moderate hypoxemia is unclear, with limited evidence for its use in the literature.^7,8