Danish Quality Assurance Project on Diagnosis and Treatment of Chronic Obstructive Pulmonary Disease (COPD) in Outpatient Lung Clinics

Inclusion Criteria: * Outpatient with the diagnosis or referral diagnosis of COPD. * COPD must be the primary reason for this outpatient contact (for both new patients and controls). Exclusion Criteria: * Any co-morbidity that hampers the diagnosis and treatment of COPD in accordance with the COPD guidelines used locally (e.g. malignant disease, dementia or sequelae of apoplexy). * Asthma without the presence of COPD