To study the predictors contribute to the progression of COPD by follow-up of patients with early COPD and analyze their changes in bioactive molecular, exhaled gas, CT image, lung function, patient's symptoms and life quality.

A research found that nearly 40% of patients with chronic respiratory symptoms who showed significant airway inflammation (airway wall thickening and/or lung structure destruction (emphysema) on chest CT had advanced COPD within 5 years, although their current lung function failed to meet diagnostic criteria for COPD. Current spirometry-based diagnostic methods are not the best predictors of COPD progression and death. CT indicated emphysema and airway inflammation were recognized as better predictors of disease progression and mortality. Based on a large cohort study, some scholars proposed the concept of "early COPD", focusing on people under the age of 50, smoking for more than 10 pack years, having one of the manifestations of early airflow limitation, abnormal chest CT, and rapid decline of FEV1, to study the mechanism of disease progression and early intervention methods.[4] In this study, we enroll participants with early COPD symptoms, to detect the progression of COPD with 3 years of follow-up. The predictors of disease progression and variants of bioactive molecular were analyzed, so as to clarify the progressive mechanism of COPD.

Inclusion Criteria:

• 1. <60 years old;

  2. Smoking ≥ 10 pack years.

  3. With any of the following anomalies: a. Post-bronchodilator FEV1/FVC< 0.7. b. CT image abnormalities: emphysema, air trapping or bronchial wall thickening; c.Rapid decrease of FEV1 (>60 ml/yr).

Exclusion Criteria:

• 1. With other known chronic lung diseases, including bronchiectasis, interstitial pulmonary disease, tuberculosis, and pulmonary vascular disease (CTEPH).

  2. With severe pleural disease and/or lesions of the sternum or ribs.

  3. Suffering from serious uncontrolled other systemic diseases, including chest and abdominal surgery, heart attack (angina pectoris, myocardial infarction, malignant arrhythmia, etc.) and cerebrovascular disease (stroke) within 3 months, as well as kidney disease (AKI), cirrhosis, and any malignant tumor except lung cancer.

  4. Suffering from severe cognitive impairment.

  5. With active tuberculosis or are taking anti-tuberculosis treatment.

  6. Pregnancy or lactation.

  7. Previous lung surgery.

  8. Acute upper and lower respiratory system infection within 4 weeks.

Consecutive eligible patients from Peking University Third Hospital will be enrolled.