Personalized Prediction Strategy for Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Inclusion Criteria: * Patients was diagnosed as COPD according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines older than 40 years old. * A signed and dated written informed consent is obtained prior to participation. * Able to comply with the requirements of the protocol and be available for study visits over 3 years. Exclusion Criteria: * A COPD subject will not be eligible for inclusion in this study if any of the following criteria apply: * Known respiratory disorders, or disorders identified at screening/visit 1 (including identification on the first CT scan), other than COPD (e.g.: lung cancer, sarcoidosis, tuberculosis, lung fibrosis, cystic fibrosis) * Known history of significant inflammatory disease, other than COPD (e.g. rheumatoid arthritis and Lupus) * Known to be severely alpha-1-antitrypsin deficient * Has experienced a moderate or severe exacerbation (requiring oral corticosteroid, antibiotics or hospitalisation) within the last 4 weeks * Having undergone lung surgery (e.g. lung reduction, lung transplant) * Have cancer or have had cancer in the 5 years prior to study entry * Having received a blood transfusion in the 4 weeks prior to study start * Inability to walk * Taking part in a blinded drug study * Having therapy with systemic corticosteroids at inclusion.