This study aims to establish the treatment scheme of Bufei Yishen granule for GOLD stage 3 or 4 chronic obstructive pulmonary disease (COPD), reducing acute exacerbation, improving exercise capacity and forming high quality evidence.

COPD is a highly prevalent disease, with a prevalence among people 40 years of age or older of 10.1% worldwide and 13.7% in China. COPD has become the third leading cause of death worldwide. Frequent acute exacerbation and exercise limitation broadly exist in COPD patients, especially those in GOLD stage 3 or 4. Although appropriate pharmacological therapies have been proven to be effective in COPD management, however, many gaps are still to be filled. For example, the adverse effects of pharmacologic therapies can never be ignored. The investigator's previous studies suggested that traditional Chinese medicine (TCM) has effect on GOLD stage 3 or 4 COPD.

This is a multicenter, randomized, double-blind, placebo controlled trial to evaluate the effect of Bufei Yishen granule on reducing acute exacerbation in GOLD stage 3 or 4 COPD subjects. After a 14-day run-in period, 348 subjects will be randomly assigned to treatment group or control group for 52-week treatment. The primary outcomes are frequency and duration of acute exacerbation. The secondary outcomes include mortality, pulmonary function, clinical symptoms, exercise capacity, quality of life and treatment satisfaction. Safety will also be assessed.

Inclusion Criteria:

• A confirmed diagnosis of GOLD stage 3 or 4 COPD.
• Syndrome differentiation meets criteria of Qi deficiency of the lung and spleen syndrome, Qi deficiency of the lung and kidney syndrome or Qi and Yin deficiency of the lung and kidney syndrome.
• Age ranges from 40 years to 80 years.
• With informed consent signed.

Exclusion Criteria:

• Pregnant and lactating women.
• Patients with severe cardiovascular and cerebrovascular diseases.
• Patients with severe liver and kidney diseases.
• Patients with asthma, bronchiectasis, active pulmonary tuberculosis, pulmonary embolism, chronic respiratory failure or other severe respiratory diseases.
• Patients with tumor after resection, radiotherapy or chemotherapy in the past 5 years.
• Patients with severe neuromuscular disorders, severe arthritis or severe peripheral vascular diseases.
• Patients with severe cognitive and psychiatric disorders.
• Patients with diabetes.
• Patients who were administered oral glucocorticoids in the past 4 weeks.
• Patients who have participated in other clinical studies in the past 4 weeks.
• People who are allergic to the treatment drugs.
• Patients who have experienced one or more acute exacerbation in the past 4 weeks.