Relationship between respiratory symptoms and medical treatment in exacerbations of COPD.

Exacerbations of chronic obstructive pulmonary disease (COPD) can be defined symptomatically or by healthcare contacts, yet the relationship between these events is unknown. Data were collected during a 1-yr study of the budesonide/formoterol combination in COPD patients, where exacerbations, defined by increases in treatment, were compared with daily records of respiratory symptoms, rescue medication use and peak expiratory flow (PEF). The relationship between changes in these variables and the medical event was examined using different modelling approaches.