November 29, 2020
Marie Angela M. Gochangco, M.D.
Chronic Obstructive Pulmonary Disease (COPD) is a preventable and treatable disease characterized by partially reversible airflow limitation.The chronic airway limitation is caused by either obstructive bronchiolitis, a mixture of small airway diseases, or emphysema, which is the destruction of lung parenchyma. COPD is associated with chronic inflammation of the airways due to prolonged exposure of noxious particles or airborne irritants.1
Cigarette smoke is the most common risk factor for COPD. Other risk factors include biomass fuel exposure, air pollution, genetic factors such as hereditary deficiency of alpha-1-antitrypsin, and poor lung development during childhood.2
Global Disease Burden
COPD remains to be a growing healthcare problem. It is currently the fourth leading cause of death in the world. The Global Burden of Disease Study in 2016 reported 251 million cases of COPD.3 According to the World Health Organization, COPD claimed 3 million lives worldwide in 2016.4 Total deaths from COPD are expected to increase in the next coming years unless actions to reduce risk factors such as cigarette smoking will be enforced.
Statistics in the Philippines
In the Philippines, COPD is the seventh leading cause of death. A study conducted in 2005 showed that COPD had a 14% prevalence rate in Metro Manila and a 20% prevalence rate in rural areas.5 In 2007, the prevalence of COPD in the Philippines was 13.8% for GOLD stage I or higher and 12.5% for GOLD stage II COPD or higher.6
The lack of data regarding COPD in the Philippines prompted the Philippine College of Chest Physicians in 2016 to conduct the C-Pass Study (COPD Profile and Survival Study). It is a 5-year study that aims to investigate COPD in the Philippines and compare the profiles of COPD patients in the Philippines with other countries. The study is expected to be completed by year 2020.5
Signs and symptoms of COPD
COPD develops slowly and commonly appears among those who are 40 years old above. Symptoms include dyspnea, chronic cough, and chronic sputum production.2 Persistent dyspnea characteristically worsening over time is a typical feature of COPD. Cor pulmonale with right heart failure and edema may be present as the disease progresses.6
Diagnosis of COPD
Family history of COPD and history of risk factors such as genetics, congenital abnormalities and exposure to tobacco smoke, smoke from biomass burning, occupational dusts, gases, and other chemicals are important in the diagnosis of COPD.2
The gold standard for the diagnosis of COPD is spirometry. This measures the forced vital capacity (FVC), which is the maximal volume of air forcibly exhaled from the point of maximal inspiration, and the forced expiratory volume in one second (FEV1), which is the volume of air exhaled during the first second of the procedure.The ratio of FEV1 and FVC is calculated. Reduction in both FEV1 and FVC is a characteristic of COPD.6
A short-acting inhaled bronchodilator is given at the time of diagnosis to confirm COPD. A post-bronchodilator FEV1/FVC<0.70 confirms the diagnosis of COPD. This finding indicates persistent airflow limitation.2 Severity of airflow limitation based on post-bronchodilator FEV1 is then classified into: Mild or Stage 1 (FEV1 ≥ 80% predicted), Moderate or Stage 2 (50% ≤ FEV1 ≤ 80% predicted), Severe or Stage 3 (30% ≤ FEV1< 50% predicted) and Very Severe or Stage 4 (FEV1< 30% predicted) among patients with FEV1/FVC < 0.70.2
Two questionnaires, namely the Modified British Research Council (mMRC) Questionnaire and the COPD Assessment Test (CAT) are used to assess dyspnea and COPD symptoms respectively.2
Patients are then classified into Groups A, B, C, and D. The ABCD assessment will be the basis for individualized pharmacological therapy. Those who have 0 or 1 moderate exacerbations (not leading to hospital admission) are classified into Groups A and B. Group A comprises of patients who have an mMRC score of 0-1 and CAT score of < 10 while those in Group B are patients who have an mMRC score ≥ 2 and CAT score of ≥ 10.2
Those who have ≥ 2 moderate exacerbations or ≥ 1 leading to hospitalization are classified into Groups C and D. Group C comprises of patients who have an mMRC score of 0-1 and CAT score of < 10 while patients under Group D have an mMRC score ≥ 2 and CAT score of ≥ 10.2
Management of COPD
Smoking cessation remains to be the mainstay of treatment in COPD.2 However, the overall success rate of smoking cessation is only about 25%.7 Introduction of legislative smoking bans are effective in reducing smoking and second-hand smoke exposure. Medications to aid in smoking cessation are available in the Philippines. These include varenicline tablets, nicotine transdermal patch, gum, and lozenges.8
No studies have shown that pharmacological therapies delay the progression of COPD. Pharmacological therapy is mainly used to control the symptoms, reduce the frequency of exacerbations and improve quality of life. Beta-2 agonists (Salbutamol, Salmeterol, Formoterol), inhaled corticosteroids (Fluticasone), antimuscarinic drugs(Ipratropium bromide, Tiotropium), methylxanthines(Theophylline), combination of beta-2 agonists and inhaled corticosteroids, and combination of beta-2 agonists and inhaled corticosteroids are the commonly used maintenance medications in COPD.2
Latest studies have shown that antibiotics for one year reduce the risk of exacerbations. COPD patients not receiving maintenance therapy also have beneficial effect on the use of mucolytics (erdosteine, carbocisteine, N-acetylcysteine).2
Initial pharmacological therapy comprise of bronchodilator for Group A patients, long-acting bronchodilator for Group B patients, long-acting muscarinic agent for Group C patients, and long-acting muscarinic agent or long-acting muscarinic agent + long-acting bronchodilator or inhaled corticosteroid + long-acting bronchodilator for Group D patients.2
Influenza vaccination is recommended yearly to reduce serious exacerbations and death in COPD.2,6 Pneumococcal vaccination is also recommended. The 23-valent pneumococcal polysaccharide vaccine (PPSV23) is given for those <65 years old with an FEV1< 40% predicted and with comorbidities. The 13-valent conjugated pneumococcal vaccine (PCV13) is given for adults≥65 years old.2
Non-pharmacologic management such as patient counseling by healthcare providers, pulmonary rehabilitation, self-help, and group programs are also important in the management of COPD.2,6 Long-term administration of oxygen (>15 hours per day) has been shown to improve lung mechanics, survival and quality of life in patients with chronic respiratory failure.2,6
Ventilatory supports such as noninvasive positive pressure ventilation (NPPV) during COPD exacerbations and continuous positive airway pressure (CPAP) in patients with COPD and obstructive sleep apnea have shown to have beneficial effects.2 Surgical therapy including lung volume reduction surgery, bullectomy, lung transplantation, and bronchoscopic interventions are indicated in selected patients.2
Updates on COPD
COPD is a major chronic condition with significant impact on one’s quality of life. It is a major cause of death and disability globally.The 2019 GOLD update is a revision of 2017 report. In the 2019 GOLD report, there is evidence that biomass fuel used during cooking is a predisposing factor for COPD. Patients with HIV and those with lower socioeconomic status also have increased risk for COPD.
Inhaled corticosteroids are no longer recommended in the initial therapy of GOLD Group C. It is recommended in Group D with elevated eosinophils. Blood eosinophil count is a predictor in the clinical response to the addition of inhaled corticosteroids. Eosinophil count of >300 cells/uL merits the use of inhaled corticosteroids.
Algorithms for initiation and adjustments in pharmacological treatment have been revised. The ABCD assessment is used in initiating pharmacological treatment. The management cycle involves a three-step process: adjust, review, and assess, and is used for adjustments in pharmacological treatment. The management cycle involves assessment of symptoms to determine change in therapy. Individualized treatment using these algorithms is essential in the management of COPD.