Using the DOSE index to predict changes in health status of patients with COPD: a prospective cohort study.

Background: The severity of chronic obstructive pulmonary disease (COPD) should not be based on the level of airflow limitation alone. A multicomponent index such as the DOSE index (dyspnoea score (D), level of airflow obstruction (O), current smoking status (S), and exacerbations (E)) has the potential to predict important future outcomes in patients with COPD more effectively than the forced expiratory volume in one second. Health status deterioration should be prevented in COPD patients.