Topical and systemic steroids constitute the first choice in medical treatment for nasal polyps. Glucocorticoids sensitivity is significantly correlated with CST1 in nasal secretions. The goal of this randomized, double-blind, placebo-controlled clinical trial is to clarify the efficacy of a short course of CST1-guided oral glucocorticoids therapy for chronic rhinosinusitis with nasal polyps. Subjects were randomized to receive either oral glucocorticoids or oral placebo for 2 weeks. Endoscopic polyp score, Total Nasal Symptom Score(TNSS), SNOT-22 score, Cystatin 1 and other biomarkers were evaluated before and after the treatment. Researchers will compare oral glucocorticoids group and oral placebo group to test CST1 predictive model of glucocorticoid therapy for Chronic Rhinosinusitis with Polyps.

Inclusion Criteria:

1. Age 18-70 years old；
2. All meet the diagnostic criteria of CRSwNP in EPOS2020;
3. Investigator-assessed endoscopic bilateral Nasal Polyp Size Score (NPSS) was greater than or equal to 4 (minimum score of 2 per nasal cavity);
4. Patients with asthma were in a stable state, with FEV1 > 50% of the predicted value or 50% of the optimal value of personal FEV1; (5) Good compliance, able to complete clinical observation.

Exclusion Criteria:

1. Medication history of oral glucocorticoids within 3 months before enrollment, antibiotics within 2 weeks;
2. Oral glucocorticoid contraindications, such as diabetes, femoral head necrosis, gastric ulcer, etc.;
3. Any nasal and/or sinus surgery within 3 months before enrollment;
4. Patients have conditions or comorbidities that may preclude evaluation of the primary efficacy endpoint, such as: unilateral posterior nasal polyp of maxillary sinus, acute rhinitis, nasal infection or upper respiratory tract at the screening period or within 2 weeks before the screening period infection, acute asthma attack within 4 weeks, current drug-induced rhinitis, allergic fungal sinusitis (AFRS), benign or malignant tumor of nasal cavity；
5. Important clinical comorbidities that may interfere with clinical effectiveness, including but not limited to: active upper or lower respiratory tract infection, cystic fibrosis, eosinophilic granuloma with polyvasculitis (Churg-Strauss syndrome), granulomatosis with polyangiitis (Wegener's granulomatosis), Young's syndrome, etc.;
6. Accompanying serious diseases or recurrent chronic diseases with poor systemic control, such as (but not limited to), active infection, cardiovascular disease, tuberculosis or other pathogen infection, diabetes, autoimmune disease, HIV, hepatitis B, Hepatitis C or parasitic diseases, malignant tumors, etc.;
7. Subjects with severe liver and kidney function injury; such as, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) >2 times the upper limit of normal, serum creatinine > the upper limit of normal value;
8. Known or suspected immunosuppression, including a history of invasive opportunistic infections (such as tuberculosis, histoplasmosis, listeriosis, coccidioidomycosis, pulmonary cysts, aspergillosis), even if the infection has subsided;
9. Women who were pregnant or planned to become pregnant during the study, or who were breastfeeding;
10. Subjects who were fertile but were reluctant to use medically approved and effective contraception;
11. Those with a history of alcohol or drug abuse;
12. Those who believed the patient had other medical or non-medical conditions that were not suitable for the study.