According to a 2005 prevalence research, the illness has a 14 percent prevalence rate in Metro Manila and a 20 percent prevalence rate in rural regions. COPD patients may be treated with both pharmacological and non-pharmacological therapy. Non-pharmacological treatments include smoking cessation programs, exercise programs, and oxygen treatment. COPD is characterized by progressive airflow limitation that results from inflammation of the lungs. The condition affects about 10 million people worldwide and over 200,000 individuals in the United States. It is estimated that it will become the leading cause of death worldwide by 2020. COPD is divided into two main types: chronic bronchitis and emphysema. Both conditions involve the development of airway inflammation that leads to excessive mucus production, increased sensitivity to gases (particularly smoke), muscle weakness, and reduced lung function. However, they are diagnosed and treated differently than each other, with different medications being used to treat them. Chronic bronchitis is characterized by persistent cough with sputum production for at least three months out of every year for two years or more. Emphysema is defined as irreversible damage to lung tissue due to prolonged exposure to noxious particles or gases. This disease causes loss of elasticity in the lungs resulting in decreased gas exchangeability.