What defines chronic obstructive pulmonary disease (COPD)?

Chronic obstructive pulmonary disease (COPD) is defined as a progressive lung disease that leads to persistent airflow limitation. This condition primarily results from prolonged exposure to harmful particles or gases, most commonly caused by smoking and environmental pollutants. The key characteristic of COPD is the ongoing reduction in airflow, which is not fully reversible, making it distinguishable from other respiratory conditions that may present with temporary limitations.

The progression of COPD involves chronic inflammation and structural changes in the airways, as well as damage to lung tissue, which contribute to the persistent nature of the airflow limitation. This chronic state is critical to its definition, as it affects an individual's ability to breathe effectively over time, leading to various symptoms such as breathlessness, chronic cough, and sputum production.

While there are conditions that involve intermittent airflow limitations or are characterized by acute respiratory infections, these do not encompass the persistent and progressive aspects of COPD, nor do they involve the long-term impacts on lung function that define the disease. Thus, the definition that emphasizes persistent airflow limitation appropriately captures the essence of COPD and its implications for patient health.