Overview of current therapies.
The therapy of chronic obstructive pulmonary disease has been comprehensively reviewed in a number of international treatment guidelines. There is consensus about what elements should be included, but the purposes of therapy and the timing of its introduction remain poorly defined. Major factors limiting effective treatment beyond those associated with the biology of the condition itself are poor diagnostic methodology, failure to identify relevant co-morbidities and reluctance to devote appropriate resources to maximizing patient gain. Too many patients are identified at the end-stages of their illness when treatment is relatively limited. Most therapy is directed at reducing the impact of the disease in terms of symptoms, exercise performance and exacerbations on the individual and only smoking cessation modifies the evolution of the disease. Treatment of hypoxaemic patients with domiciliary oxygen improves mortality and slows the development of pulmonary hypertension. Effective smoking cessation is relevant at all stages of the disease. It depends on the willingness of the individual to participate, and quit rates can be improved by the use of nicotine replacement therapy and possibly bupropion. Inhaled bronchodilator drugs palliate symptoms and improve exercise performance in pharmacologically predictable ways. In patients with severe disease, reduction in operating lung volumes is more important than 'bronchodilitation' and is better sustained by long acting beta agonists and anticholinergics. Inhaled corticosteroids reduce exacerbation rates and improve health status in established disease but do not modify disease evolution. Pulmonary rehabilitation improves exercise performance and health status without changing underlying pulmonary mechanics. Whether hospitalizations and exacerbations can be modified is still to be established. Nutritional therapy is in its infancy but calorie supplementation alone is insufficient to improve patient well being. Selected individuals can undergo lung volume reduction surgery with benefits extending up to two years but the risks are dependent on the skill of the operators and the appropriateness of patient selection. Lung transplantation is symptomatically helpful but does not modify the natural history of the disease. Hospitalization due to exacerbations of disease is frequent and their treatment with bronchodilators, antibiotics and corticosteroids now have a basis in randomized trial data. Mortality reflects the incidence of respiratory acidosis and noninvasive ventilation has a role in safely managing patients outside of the intensive care unit. Effective prevention of exacerbation should be possible with newer antiviral agents but data are presently lacking.