Respiratory diseases have deserved increased attention by researchers in the last decade. The high prevalence and elevated morbidity, mortality, and costs derived from these diseases are overwhelming.

Respiratory medicine has progressed to a great extent in various aspects, however, in an inharmonious manner. On one hand, the advances in molecular biology, genetics, and, less remarkably, in the understanding of mechanisms of disease have made an increase in knowledge possible, though this is limited to small numbers of practicing pulmonologists. On the other hand, the clinical applications of this progress and the impact on clinical research of evidence-based medicine have theoretically contributed to notions and information concerning the diagnosis and, primarily, treatment of patients through international trials and periodic updating of guidelines. It is, nonetheless, unfortunate that this large volume of information has not substantially influenced the behavior of pulmonary physicians in private practice, as well as in many hospitals. There is less and less impact of large textbooks on medical knowledge, as the number of new ideas, added every year, make it difficult to regularly revise and update information, which is often of unequal value.

The new medical series, Hot Topics in Respiratory Medicine, is aimed at making it possible for any pulmonologist and physician interested in respiratory diseases to learn what is new and important in the profession and science of pulmonology. This series has dedicated a number of publications to chronic obstructive pulmonary disease (COPD). The current one dedicated to the management of exacerbations of COPD is the first of a group of publications that will deal with different aspects of COPD, such as the diagnosis of the disease in primary care, management of stable COPD, and alpha-1-antitrypsin deficiency, among others.

Chronic obstructive pulmonary disease is one of the most prevalent diseases in developed countries. Furthermore, the number of individuals affected has grown over recent decades. Mortality due to COPD has increased despite the campaigns against tobacco consumption. Amazingly, COPD is the only potentially preventable disease in which mortality is still on the rise. In Spain, there is a 9% prevalence of COPD in adults between the ages of 40 and 70 years, although only 22% are diagnosed. In the United States, more than 15 million people are estimated to suffer from COPD and it has accounted for more than 95,000 deaths in 1993.

The chronic and progressive course of COPD is often aggravated by short periods of increasing symptoms, particularly increasing cough, dyspnea, and sputum production, which can become purulent. The majority of these exacerbations are produced by bronchial infection and, if frequent, have been demonstrated to have a negative impact on quality of life in patients with COPD. Furthermore, acute exacerbations are the most frequent cause of medical visits, hospital admissions, and death among patients with chronic lung disease.

Most studies consistently show a failure rate of ambulatory treatment of exacerbations that ranges from 15% to 26%. Since relapse after initial treatment for acute exacerbation may lead to prolonged disability, a new course of antibiotics, an emergency visit, or even hospital admission, it is crucial to identify patients most at risk for relapse. One main concern regarding exacerbations is the high economic impact derived from their management, particularly that of hospitalizations. Identification of risk factors may permit the implementation of more aggressive broad-spectrum treatment and closer follow-up. As a further step, risk factors associated with relapse should be incorporated into management guidelines to aid physicians in identifying at-risk patients.

I am sure that the readers will find this series both interesting and useful in their everyday clinical practices.