Cohort Study of Airway Microecology and the Pathogenesis and Evolution of Chronic Obstructive Pulmonary Disease

Inclusion Criteria: 1. Have the ability to communicate orally or in writing and sign an informed consent form; 2. Age from 18 to 70 years (the age of patients with mild to moderate COPD \<75 years), regardless of gender; 3. Meet the above-mentioned early diagnosis criteria for high-risk patients with COPD/early-stage COPD/mild to moderate COPD. Exclusion Criteria: 1. Patients suffering from any of the following diseases: active tuberculosis, severe bronchiectasis, lung abscess, aspiration pneumonia, lung tumor, non-infectious interstitial lung disease, pulmonary edema, atelectasis, pneumothorax, pleural effusion , Pulmonary embolism, pulmonary eosinophilic infiltration, and pulmonary vasculitis; 2. Patients with a history of tumors or patients with current tumors; 3. The patient has severe renal impairment: creatinine clearance rate \<30ml/min/1.73m2 or serum creatinine\>265μmol/L (\>3mg/dL); 4. Patients suffering from liver disease or severe liver damage: ALT, AST\> 2 times the upper limit of normal; 5. pregnancy; 6. Severe COPD, FEV1 predicted value ≤50%; 7. Severe heart disease, such as coronary heart disease, heart failure, etc.; 8. Severe coagulopathy: INR\>1.4, PTT\>40s, PLT\<150x103 cells 9. Bronchial Asthma; 10. Severe alcoholism; 11. diabetes; 12. Have used antibiotics within two months, 13. Used systemic and local hormones; 14. Cannot sign the informed consent form;