Background: Although it has been repeatedly suggested that chronic obstructive pulmonary disease (COPD) is associated with depression, no conclusion has so far been reached. A study was undertaken to investigate whether depression occurs more often in patients with COPD than in controls. The demographic and clinical variables associated with depression were also determined. Methods: Patients with a registered diagnosis of obstructive airway disease in general practice, aged >40 years, forced expiratory volume in 1 second (FEV 1 ) <80% predicted, FEV 1 reversibility <12%, FEV 1 /VC < predicted -1.64 × SD, and a history of smoking were selected. A random sample of subjects without a registered diagnosis of asthma or COPD aged 40 years or older acted as controls. Depression was assessed using the Centers for Epidemiologic Studies Depression (CES-D) scale. Results: In patients with severe COPD (FEV 1 <50% predicted), the prevalence of depression was 25.0% compared with 17.5% in controls and 19.6% in patients with mild to moderate COPD. When the results were adjusted for demographic variables and comorbidity, the risk for depression was 2.5 times greater for patients with severe COPD than for controls (OR 2.5, 95% CI 1.2 to 5.4). In patients with mild to moderate COPD this increased risk of depression was not seen. Living alone, reversibility of FEV 1 % predicted, respiratory symptoms and physical impairment were significantly associated with the scores on the CES-D scale. Conclusion: Patients with severe COPD are at increased risk of developing depression. The results of this study underscore the importance of reducing symptoms and improving physical functioning in patients with COPD.

The goal of this study is to determine the prevalence of 23 common diseases in subjects with a chronic airway obstruction and in controls. All subjects with a known diagnosis by their general practitioner of asthma or chronic obstructive pulmonary disease (COPD), and who were 40 years and older were selected (n = 1145). Subjects who were willing to participate (n = 591) and who appeared to have an irreversible airway obstruction (n = 290) were included. To recruit controls, a random sample was taken of 676 individuals who were 40 years and older and who were not diagnosed as having asthma or COPD by their general practitioner. Of these 676 individuals 421 were willing to participate. The presence of diseases was determined by using a questionnaire. One hundred and ninety-four subjects (73%) and 229 controls (63%) were shown to be suffering from one or more (other) diseases. In both groups, locomotive diseases, high blood pressure, insomnia and heart disease were most common. Locomotive diseases, insomnia, sinusitis, migraine, depression, stomach or duodenal ulcers and cancer were significantly more common in the subject group than in the control group. For both clinical and research purposes, it is important to consider the presence of diseases in patients with a chronic airway obstruction.

COPD patients can be impaired in all domains of HRQL. However, impairments in physical functioning, vitality, and general health are related to COPD and to some extent to comorbidity, while impairments in social and emotional functioning do not seem to be related to COPD, but only to comorbidity.