Association of anxiety and depression with pulmonary-specific symptoms in chronic obstructive pulmonary disease.

OBJECTIVES: To examine the association of anxiety and depression with pulmonary-specific symptoms of Chronic Obstructive Pulmonary Disease (COPD), and to determine the extent to which disease severity and functional capacity modify this association.

METHOD: Patients (N = 162) enrolled in the INSPIRE-II study, an ongoing randomized, clinical trial of COPD patients and their caregivers who received either telephone-based coping skills training or education and symptom monitoring. Patients completed a psychosocial test battery including: Brief Fatigue Inventory, St. George's Respiratory Questionnaire, UCSD Shortness of Breath Questionnaire, State-Trait Anxiety Inventory, and Beck Depression Inventory. Measures of disease severity and functional capacity (i.e., FEV1 and six-minute walk test) were also obtained.

RESULTS: After covariate adjustment, higher anxiety and depression levels were associated with greater fatigue levels (ps < .001, deltaR2 = 0.16 and 0.29, respectively), shortness of breath (ps < .001, deltaR2 = 0.12 and 0.10), and frequency of COPD symptoms (ps < .001, deltaR2 = 0.11 and 0.13). In addition, functional capacity was a moderator of anxiety and pulmonary-specific COPD symptoms. The association between anxiety and shortness of breath (p = 0.009) and frequency of COPD symptoms (p = 0.02) was greater among patients with lower functional capacity.

CONCLUSIONS: Anxiety and depression were associated with higher levels of fatigue, shortness of breath, and frequency of COPD symptoms. It is important for clinicians to be aware of the presence of anxiety and depression in COPD patients, which appears to correlate with pulmonary-specific COPD symptoms, especially in patients with lower functional capacity. Prospective design studies are needed to elucidate the causal relationships between anxiety and depression and pulmonary-specific symptoms in COPD patients.