This study is a multi-centers, cross-sectional study, conducted in Kwong Wah Hospital and Wong Tai Sin Hospital, Hong Kong SAR. Age and comorbidity-matched COPD and control subjects were recruited from clinics. Depressive symptoms were measured by a validated Chinese version of Geriatric Depression Scale short form (GDS - 15 items) with 2 cut-off points. A score of 8 or above was considered significant depressive symptoms while the cut off score of 5 or above was for patients with mild depressive symptoms. Prevalence rates of depressive symptoms were measured in both COPD and control groups. Predictors for depression (GDS = or\> 8) were determined using univariate and multivariate analysis.
