Resumen del Proyecto
Chronic obstructive pulmonary disease (COPD) is a highly prevalent disease affecting >10% of the population worldwide. Nonetheless, recent epidemiological studies have found a high prevalence of undiagnosed COPD, with about 85% of patients not formally diagnosed. Most undiagnosed individuals have mild disease and epidemiological data suggests that patients with mild COPD who are already dyspneic are at risk of accelerated lung function decline, worse health status, and increased health-care use. A greater awareness of the population and the medical community to identify these individuals in order to receive proper treatment, including smoking cessation interventions, seems advisable.
However, we need to first establish if only those individuals with dyspnea exhibit typical manifestations of the disease. This is also important for individuals considered having mild disease, but who did not exhibit dyspnea, because they may be wrongly labeled as diseased.
Since the definition of mild COPD is based on arbitrary spirometric criteria, in the present project we propose that dyspnea may point out at individuals truly diseased, while those without dyspnea probably behave similar to smokers without COPD. We will first identify the presence of dyspnea among individuals categorized as having mild COPD by spirometric criteria and then to compare quality of life, physical activity, emphysema, airways disease, peripheral muscle mass, and exercise capacity, between dyspneic and non-dyspneic subjects, and smoker controls.
We hypothesize that all the above variables will be significantly affected by the presence of dyspnea. However, age and gender matching is critical, because in healthy people exercise capacity, physical activity, and peripheral muscle mass are lower in females and decrease as a consequence of ageing. Emphysema, on the other side, is lower in females and increase in the elder. It is also critical to discard heart failure as the cause of dyspnea, particularly because of the combined effects of ageing and smoking. To accomplish our aim we will take advantage of: a) computer tomography, to measure emphysema, airways disease, and peripheral muscle mass; b) exercise stress echocardiography, to evaluate heart function; c) the negative expiratory pressure technique, to evaluate exercise induced tidal expiratory flow limitation; d) accelerometers, to evaluate physical activity; and e) several questionnaires to determine the impact of COPD on health related quality of life.
The effects of bronchodilators and pulmonary rehabilitation have been largely circumvented in patients with mild COPD. Consequently, an additional aim of the present study is to evaluate in those patients with dyspnea the acute effects of bronchodilators and the short term effects of pulmonary rehabilitation on exercise capacity and quality of life. There is no apparent reason to assume that both interventions should not benefit these patients, since they are used in more advanced disease to palliate dyspnea.
In summary, we are proposing to comprehensively evaluate the earliest stage of COPD; to define the importance of dyspnea in the screening of true diseased patients, and to provide potential clinically relevant evidence regarding the effectiveness of interventions at this stage.
