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COPD has traditionally been described as the combination of two manifestations: parenchymal destruction (emphysema) and small airway disease (obstructive bronchitis). Emphysema is characterized by damaged lung tissue and alveoli (tiny air sacs) at the end of the airways, causing air to be trapped in the lungs and leading to shortness of breath¹. Bronchitis is characterized by inflammation in the bronchial tubes, making it difficult to breathe, and at times a chronic cough that brings up sputum (mucus)². Recently the Global Initiative for Obstructive Lung Disease (GOLD) Workshop Report defined COPD as a disease characterized by airflow limitation that is not fully reversible³. In view of common clinical observations in Japan, the new definition acknowledges that some patients can develop significant airflow limitations without the classic symptoms of chronic cough and sputum production.

COPD is a chronic disease that develops over many years. It is most often caused by smoking, and 80-90% of people with COPD have been long-term smokers⁴. It is believed that long-term inhalation of lung irritants such as industrial dust and chemical fumes may also lead to COPD. Due to changes in smoking habits, the prevalence of the disease is expected to increase over the next twenty years in the United States and Europe, and then reach a plateau. In Japan and Asia, the disease prevalence is expected to continue increasing for the next 40 years. For example, a survey found that in China, the average daily consumption of tobacco per person increased from one cigarette in 1952 to ten cigarettes in 1990, a rate similar to that found in the U.S. in the 1950's⁵. In Japan, the estimated total cost of COPD is more than 805 billion yen per year, imposing a high economic burden on the Japanese healthcare system⁶.

Early diagnosis and treatment greatly determine the outcome for COPD patients. The disease can only be reliably diagnosed through a medical history and lung function tests (e.g., spirometry). There is no cure for COPD, but steps can be taken to manage the disease. The only way to slow the progression of the disease is to stop smoking. Medications such as anticholinergics (ipratropium, tiotropium), inhaled corticosteroids and beta-agonists, as well as ventilators and oxygen therapy may make it easier to breathe⁷. COPD is a progressive disease and may be complicated by a COPD exacerbation (sudden and prolonged increase in symptoms including shortness of breath, cough and sputum production). COPD exacerbations may be life-threatening and may require immediate treatment. In addition, cor pulmonale (heart failure that affects the right side of the heart) frequently occurs in COPD patients⁸.

Discussion questions

1. Please summarize the article. What is the main point of the article?
2. What is COPD?
3. How has the definition of COPD changed? Why?
4. What causes COPD?
5. Explain the difference in prevalence in Asia, the United States and Europe. What causes this difference?
6. How is COPD treated?
7. What is the best way to prevent COPD?

References:

1. What is chronic obstructive pulmonary disease? WebMD.. (Accessed 19 May 2007)
2. What is chronic obstructive pulmonary disease? WebMD. (Accessed 19 May 2007)
3. Tatsumi K et al. Clinical phenotypes of COPD: Results of a Japanese epidemiological survey. Respirology (2004) 9, 331-336.
4. What is chronic obstructive pulmonary disease? WebMD (Accessed 19 May 2007)
5. Teramoto S et al. Global burden of COPD in Japan and Asia. The Lancet. Volume 362, Issue 9397, 22 November 2003, pages 1763-1765. Available online 25 November 2003. (Accessed 19 May 2007)
6. Nishimura S and Zaher C. Cost impact of COPD in Japan: Opportunities and challenges? Respirology 2004 November 9, volume 9 issue 4 pages 466-73. (Accessed 19 May 2007)
7. COPD treatment overview. WebMD. (Accessed 19 May 2007)
8. COPD treatment overview. WebMD. (Accessed 19 May 2007)