Objective: To determine the extent to which mood, symptoms, lung function, and social support of patients with chronic obstructive pulmonary disease (COPD) predicted their level of functioning over a 30-month period.
Design: Prospective, longitudinal.
Setting: The homes of patients living in or adjacent to metropolitan Toronto.
Subjects: Seventy-one patients (48 men and 23 women) with COPD who had a forced expiratory volume in 1 second less than 50% of predicted (FEV1 < 50%) and who spoke English. They ranged in age from 43 to 81 years (mean 66.37 years).
Outcome measures: The patients' level of functioning at the final data collection visit, 30 months after the initial measure.
Instruments: At both data collection visits patients completed measures of mood (negative mood scales of the Profile of Mood States), symptoms (Bronchitis-Emphysema Symptom Checklist), social support (Personal Resource Questionnaire), and functioning (Sickness Impact Profile).
Results: Data were analyzed by use of multiple regression analysis. From measures taken at the initial visit (T1), the best predictors of patients' functioning at 30 months (T2) were their functioning at T1, symptoms, FEV1, and age. Together these accounted for 70% of the variance in the final functioning scores, with initial functioning scores accounting for 51% of the variance. The most prevalent symptoms were dyspnea and fatigue, and both were highly correlated with functioning scores 30 months later.
Conclusions: In this study, symptoms, FEV1, and age are predictive of functioning in patients with COPD over a 30-month time frame. However, only 50% of the 143 patients recruited into the study completed it. Therefore caution needs to be exercised when the results are applied to other patients with COPD.