Pulmonary rehabilitation (PR) improves health-related quality of life (HRQoL) and exercise capacity. Little is known about the impact of depression symptoms and exercise self-efficacy on improvements in these key PR outcomes. This study examined the impact of baseline depression status and change in depression symptoms (Beck Depression Inventory-II [BDI-II] score) over the course of PR on change in HRQoL assessed by the Chronic Respiratory Disease Questionnaire-Self Reported (CRQ-SR) and exercise capacity as measured by the 6-Minute Walk Test (6MWT). We also examined whether baseline exercise self-efficacy moderated the association between baseline depression symptoms and change in these key PR outcomes. We studied 112 US veterans (aged 70.38 ± 8.49 years) with chronic obstructive pulmonary disease (COPD) who completed PR consisting of twice-weekly 2-hour classes for 18 sessions. Depressed (BDI-II >13) and nondepressed (BDI-II ≤13) patients at baseline demonstrated comparable and significant improvement in CRQ-SR total score, subscales, and 6MWT. Greater reduction in depression over the course of treatment was significantly associated with greater improvement in CRQ-SR total score and the following subscales: fatigue, mastery, and emotional function. Change in depression did not predict change in 6MWT distance. Baseline exercise self-efficacy moderated the association between baseline depression symptoms and change in CRQ-SR fatigue. Specifically, when baseline exercise self-efficacy was <30.4, greater baseline depression was associated with less improvement in CRQ-SR fatigue. When baseline self-efficacy was >152.0, greater baseline depression was associated with greater improvement in CRQ-SR fatigue. PR programs should address mood and confidence to exercise given their impact on key PR outcomes.
Keywords: COPD; depression; exercise self-efficacy; health-related quality of life; pulmonary rehabilitation.