Description

• The Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines COPD as follows:
  • “COPD is a common, preventable, and treatable disease that is characterized by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases and influenced by host factors including abnormal lung development” (1).
• This new definition no longer includes the terms “emphysema” and “chronic bronchitis.”
• COPD is now the third leading cause of death worldwide, with 90% of these deaths occurring in low- and middle-income countries. COPD was responsible for 3.2 million deaths globally in 2019.

Epidemiology

Incidence
The incidence of COPD is 8.9/1,000 person-years.

Etiology and Pathophysiology

Exposure to noxious gasses or particles leading to pathologic processes in the lung:

• Impaired gas (carbon dioxide [CO₂] and oxygen) exchange, persistent airway obstruction, destruction of lung parenchyma

Genetics
α₁-Antitrypsin deficiency is a rare inherited disorder due to two autosomal codominant alleles.

Risk Factors

• Smoking tobacco or marijuana: including passive smoking and water pipe
• History of severe childhood respiratory infections
• Aging—including healthy aging as well as the cumulative summation of lung exposure over time
• Lower level of education and lower socioeconomic status
• Asthma and airway hyperreactivity
• Indoor air pollution (especially indoor biomass cooking worldwide)
• Occupational organic or inorganic dusts

General Prevention

Smoking cessation and general avoidance of noxious material is the most important preventative measure.

Commonly Associated Conditions

• Pulmonary: lung cancer, chronic respiratory failure, acute bronchitis, sleep apnea, pulmonary hypertension (HTN), asthma
• Cardiac: coronary artery disease, arrhythmia
• Ear/nose/throat (ENT): chronic sinusitis, laryngeal carcinoma