Subgroup analysis of symptoms and their effect on functioning, exercise capacity, and physical activity in patients with severe chronic obstructive pulmonary disease

BackgroundLittle is known about symptom clusters and their effect on outcomes in people with chronic obstructive pulmonary disease (COPD).PurposesTo determine whether subgroups of patients with COPD could be identified by symptom ratings, whether they differed on selected demographic and clinical characteristics, and whether they differed on functioning, exercise capacity, and physical activity.MethodSubjects with severe COPD (n = 596) were drawn from the National Emphysema Treatment Trial dataset. Data were drawn from questionnaires and clinical measures.ResultsTwo subgroup clusters emerged from four symptoms. Mean age and the proportion of participants with higher education, higher income levels, and using oxygen at rest were significantly different between subgroups. Participants with high levels of symptoms had lower functioning and decreased exercise capacity. Symptom cluster subgroups were significantly associated with social functioning.ConclusionThese findings suggest that screening for high levels of symptoms may be important in patients with severe COPD.