Well-conducted epidemiological studies indicate that the worldwide prevalence of physiologically defined chronic obstructive pulmonary disease (COPD) in adults aged 40 years and older ranges from approximately 9 to 10%. However, the Burden of Lung Disease (BOLD) initiative (using the Global Obstructive Lung Disease [GOLD] criteria for COPD) has reported significant differences between countries, ranging from 11.4% in China to 26.1% in Austria. These differences may be related, at least in part, to differences in genetic background, smoking habits, and exposure to other environmental risk factors. More importantly, most patients with COPD remain undiagnosed. Only 22% of patients with COPD are diagnosed in Spain, 20% in the United Kingdom, 19% in Greece, 11.3% in Latin America, and only 9.4% in Japan.
Although undiagnosed patients had a milder airflow obstruction, remarkably they had a significant impairment in health-related quality of life and reduced levels of activities of daily living. These data highlight the importance of early recognition of the disease and the need for extensive use of spirometry in order to decrease the burden of undiagnosed airflow obstruction in the community. Interestingly, a survey of the general population demonstrated that only 42.6% of adults who consulted a physician in Spain for chronic respiratory symptoms underwent spirometry, and programs of office spirometry have been hampered by the lack of expertise, time, and motivation of primary care physicians.
The natural history of COPD has been the focus of attention since the first descriptions by Fletcher and Peto detailing the gradual decline of lung function. One crucial observation was that exacerbations impact the rate of decline in lung function and, therefore, prevention of exacerbations must be a key objective in the treatment of COPD. Other hypotheses suggest that persistent bronchodilatation may reduce exacerbations and hyperinflation, improve exercise capacity, and even reduce inflammatory damage in the lungs and/or respiratory muscles. All of these effects might finally result in a change in the natural history of the disease and an improvement in prognosis.
These aspects of the natural history of COPD are described in detail in the current issue of Hot Topics in Respiratory Medicine. The authors take readers from the description of the natural course of COPD to the possible impact of pharmacotherapy with long-acting bronchodilators in the clinical course. Physicians will find relevant information to apply in their clinical practice that will help in their care of patients with COPD, a preventable and treatable disease.