 Patients scheduled for major surgery, who present in the pre-assessment clinic of the University Medical Center Hamburg-Eppendorf during the study recruitment period, will be screened for eligibility. Patients with typical clinical signs and a positive COPD Assessment Test CATTM qualify for spirometry. After informed consent 80 patients with disproved COPD FEV1FVC ratio 0.70 and 240 patients with confirmed COPD FEV1FVC ratio 0.70 will consecutively be analysed. 