COPD: A modern lifestyle lung disease
The recent directive of President Duterte banning smoking in public places throughout the country is considered by many, particularly in the medical community, as a significant milestone and a positive step in the promotion of health and disease prevention among Filipinos. This presidential action will significantly reduce the prevalence rate of the so-called modern lifestyle diseases that are closely associated with smoking. Among these is chronic obstructive pulmonary disease, more commonly known by its acronym COPD.
COPD is undoubtedly a major cause of morbidity and mortality. However, it is a disease that is both preventable and treatable. Worldwide, according to GOLD guidelines
2017, COPD is the fourth leading cause of death in 2015 and is projected to be the 3rd leading cause of death by 2020. It also says that more than three million people died of COPD in 2012, accounting for six percent of all deaths globally. In the Philippines, according to Regional
COPD Workgroup Respirology 2003, the estimated prevalence rate of COPD is at 6.3 percent. This is most likely an underestimation since COPD is oftentimes under-recognized and under-diagnosed locally.
Previously classified either as chronic bronchitis or emphysema, COPD is a type of long term lung disease characterized by persistence of airway narrowing due to prolonged and continued exposure to noxious irritants such as smoking. This in turn results in the development of two characteristic respiratory symptoms: chronic progressive shortness of breath and prolonged cough.
Tobacco smoking, the most common cause of COPD, induces an enhanced and prolonged inflammatory response in the lung, resulting to widespread structural abnormalities leading to chronic airway narrowing and tissue breakdown, particularly in region of the gas-exchanging areas or alveoli (emphysema). Current studies also implicate chronic exposure to air pollution, both outdoor and indoor, as well as genetics, poor lung development during early childhood, and poor socio-economic conditions as other COPD risk factors.
COPD is also characterized by sudden worsening of respiratory symptoms which is described as exacerbation. This condition is commonly accompanied by increased sputum production, change in the color of sputum (oftentimes green or yellow), palpitations, fever and increased sweating. These symptoms often lead to outpatient consult and/or hospital admission.
Shortness of breath, which in medical parlance is known as dyspnea, is the most distressing symptom that a COPD patient feels. It is usually described as “air hunger,” “I’m out of breath,” or simply,” I can’t breathe.” It is initially felt during moderate physical exertion such climbing a flight of stairs or walking on level ground, and as the disease progresses, it can occur even during mild activities such as taking a shower or walking short distances. In more advanced cases of COPD, shortness of breath can also happen during restful activities such as sitting or combing one’s hair.
Cough is the initial symptom that develops in COPD, and it usually precipitated by an acute respiratory infection, sudden change in the humidity level, or continuous exposure to pollutants. It is usually episodic and lasts for a short duration. However, cough can oftentimes be chronic, lasting for months. This is clinically known as chronic bronchitis, the type of cough that has persisted for at least three months to two years. Among smokers, this is usually associated with the term “smoker’s cough.”
A lung function test or spirometry is usually done to confirm the presence of COPD. This is a non-invasive test that is readily available in many hospitals. It is used to evaluate individuals who are at least 35 years old, having persistent respiratory symptoms, and a history of prolonged exposure to smoking or air pollutants. Spirometry measures the maximal amount of air that an individual can exhale after maximal inhalation. There are two physiologic measurements that are used to determine the presence of airway limitation: Forced Vital Capacity (FVC) and Forced Expiratory Volume in one second (FEV1). An FEV1/FVC ratio that is equal or less than 70 percent indicates the presence of persistent airway limitation. The FEV1 value is also helpful in evaluating the severity of airflow narrowing. The lower the value (less than 50 percent), the greater the airway narrowing.
A Chest X-ray has limited utility in assessing COPD. It is only used to exclude diseases that may be associated with COPD such as bronchiectasis, pulmonary tuberculosis, lung mass, heart enlargement or skeletal abnormalities such as scoliosis or osteoarthritis.
Although there is still no definitive cure for COPD, medications are used to relieve the symptoms of cough and shortness of breath, as well as to prevent exacerbations and disease progression and hopefully, to improve quality of life and health status. These medications are in the form of dry powder, capsule or mist that the individual inhales through a device. These drugs act by widening the airway diameter and are used daily for a prolonged period. Based on its pharmacologic activity, it comes in two general classes: beta-2 agonist (e.g. salbutamol, formoterol, indacaterol, olodaterol, salmeterol) and anti-cholinergics (e.g. ipratropium, thiothropium, glycopyrronium, umeclidium). Current medications may include one of the two general types or a combination of betaagonist and anti-cholinergics in one inhaler device. For advanced COPD, inhaled corticosteroids may be added, especially where maximal symptomatic improvement has not been achieved despite current treatment.
Other management strategies used in COPD include smoking cessation, yearly anti-influenza vaccination, anti-pneumonia vaccination, enrolment in a pulmonary rehabilitation program and long-term oxygen therapy.
Most cases of COPD can be prevented by decreasing exposure to smoke and improving air quality. Keeping people from smoking especially among children, teenagers and pregnant women is an important long-term goal and mission in COPD prevention which requires a multi-sectoral approach of the medical community, academe, business sector and government.