Procalcitonin-Guided Antibiotic Therapy in Bronchiectasis

Inclusion Criteria: 1. Bronchiectasis was diagnosed by high-resolution computed tomography based on the criteria published by McShane PJ et al. 2. Acute exacerbations of bronchiectasis. 3. Aged \>= 18 years. 4. Procalcitonin been detected after admission. Exclusion Criteria: 1. Associated with chronic obstructive pulmonary disease. 2. Associated with asthma. 3. Traction bronchiectasis caused by pulmonary fibrosis. 4. Rule out other possible cause procalcitonin increased diseases such as cancer, connective tissue disease, active tuberculosis, chronic liver disease and respiratory system than the bacterial infection. 5. Clinical data were incomplete. 6. Can not follow up with the person.