In COPD patients with resting hypoxemia, which therapy has been documented to alter the natural history of the disease?

• A. Bronchodilators
• B. Corticosteroids
• C. Oxygen
• D. Chronic antibiotic use

Answer: (C)

In patients with COPD who have resting hypoxemia, the therapy that has been shown to actually change the disease's course is long-term supplemental oxygen. When oxygen levels stay chronically low (PaO2 around 55 mmHg or less, or oxygen saturation 88% or less at rest), providing oxygen over the long term has been demonstrated to improve survival. This survival benefit comes from correcting hypoxemia, which reduces hypoxic pulmonary vasoconstriction, lowers the risk of developing or worsening pulmonary hypertension, diminishes polycythemia, and supports cardiac and organ function, thereby reducing mortality from right-sided heart failure and other hypoxemia-related complications. Classic clinical trials established that using oxygen for many hours per day (typically at least around 15 hours daily) extends life in these patients.

Bronchodilators and corticosteroids mainly improve symptoms, airway function, and exacerbation management but have not shown the same proven effect on long-term survival in hypoxemic COPD. Chronic antibiotics can help reduce exacerbations in some patients, yet they do not have the broad, proven impact on mortality that long-term oxygen therapy does.