Depression and Health-Related Quality of Life in Chronic Obstructive Pulmonary Disease

BACKGROUND: Prior research on the risk of depression in chronic obstructive pulmonary disease ( COPD) has yielded conflicting results. Furthermore, we have an incomplete understanding of how much depression versus respiratory factors contributes to poor health-related quality of life. METHODS: Among 1202 adults with COPD and 302 demographically matched referents without COPD, depressive symptoms were assessed using the 15-item Geriatric Depression Score. We measured COPD severity using a multifaceted approach, including spirometry, dyspnea, and exercise capacity. We used the Airway Questionnaire 20 and the Physical Component Summary Score to assess respiratory-specific and overall physical quality of life, respectively. RESULTS: In multivariate analysis adjusting for potential confounders including sociodemographics and all examined comorbidities, COPD subjects were at higher risk for depressive symptoms (Geriatric Depression Score >= 6) than referents (odds ratio [OR] 3.6; 95% confidence interval [CI], 2.1-6.1; P <.001). Stratifying COPD subjects by degree of obstruction on spirometry, all subgroups were at increased risk of depressive symptoms relative to referents (P < .001 for all). In multivariate analysis controlling for COPD severity as well as sociodemographics and comorbidities, depressive symptoms were strongly associated with worse respiratory-specific quality of life (OR 3.6; 95% CI, 2.7-4.8; P < .001) and worse overall physical quality of life (OR 2.4; 95% CI, 1.8-3.2; P < .001). CONCLUSIONS: Patients with COPD are at significantly higher risk of having depressive symptoms than referents. Such symptoms are strongly associated with worse respiratory- specific and overall physical health-related quality of life, even after taking COPD severity into account. (C) 2009 Elsevier Inc. All rights reserved. The American Journal of Medicine (2009) 122, 778.e9-778.e15