Functional status and survival in COPD.

A limitation in functional status is an important factor in the handicap caused by advanced chronic lung disease such as COPD. Indicators of functional status in these patients include exercise performance levels common to everyday activity (such as the six minute walk distance) and scores on self-completed questionnaires rating interference with daily activities (such as the Functional Activities component of the PFSS). Both a longer timed walk distance and a higher functional performance score were highly predictive of survival in independent studies of pulmonary rehabilitation patients. This probably reflects the ability of measures of functional status to quantify non-pulmonary as well as morbidity, both of which contribute to the overall mortality in individuals with advanced lung disease.