COPD exacerbations: causes, prevention, and treatment.

The mechanisms of COPD exacerbation are complex. Respiratory viruses (in particular rhinovirus) and bacteria play a major role in the causative etiology of COPD exacerbations. In some patients, noninfective environmental factors may also be important. Data recently published from a large observational study identified a phenotype of patients more susceptible to frequent exacerbations. Many current therapeutic strategies can reduce exacerbation frequency. Future studies may target the frequent exacerbator phenotype, or those patients colonized with potential bacterial pathogens, for such therapies as long-term antibiotics, thus preventing exacerbations by decreasing bacterial load or preventing new strain acquisition in the stable state. Respiratory viral infections are also an important therapeutic target for COPD. Further work is required to develop new anti-inflammatory agents for exacerbation prevention, and novel acute treatments to improve outcomes at exacerbation.