To answer the question whether a disease specific profile of breath in patients with COPD can be detected by an untargeted metabolomic study using exhaled breath analysis by mass spectrometry.

This is an observational study comparing the volatile organic compounds (VOCs) in exhaled breath between COPD patients and matched control subjects (age, gender, smoking-state). 40 COPD patients (20 non-frequent, 20 frequent exacerbators) and 40 matched controls will be examined by SESI-MS on the composition of exhaled breath for identification of COPD specific markers.

Inclusion Criteria:

• confirmed COPD GOLD stage I-IV, based on a post-bronchodilator spirometry (FEV1/FVC < 0.7) performed within the last 6 months
• age between 18 and 80 years at study entry
• healthy controls: normal spirometry

Exclusion Criteria:

• COPD exacerbation within the last 6 weeks
• any lung disease other than COPD
• acute inflammatory disease (e.g. common cold) within the last 6 weeks
• acute or chronic hepatic disease
• renal failure or renal replacement therapy

Patients will be recruited in primary, secondary and tertiary care clinics. Healthy controls will be recruited from a community sample.