China Chronic Cough Registry: a Multicenter, Prospective, Observational Study

Primary outcomes

1. Baseline demographics, clinical and pathophysiologic characteristics of the total patients in the chronic cough cohort

   Time frame: After 6000 patients entry at baselin

   The demographics, and clinical characteristics included age, sex, BMI, smoking history, cough triggers, cough timing, cough complications and associated symptoms, comorbidities, previous treatment and response, cough severity outcomes evaluated by questionnaires including cough VAS, urge to cough VAS, CET, LCQ. Blood eosinophils counting, lung function and FeNO measurements were performed and recorded.

2. The prognosis of chronic cough in a real-word clinic

   Time frame: From baseline to the end of follow-up at the second year

   Elucidating the prognosis of the total patients after 2 yeas follow-up. Cough relief will be reported by patients-self and risk factors for patients with persistent cough will be investigated. After 2 years from the baseline, patients will be visited at clinic or through telephone, cough VAS, urge to cough VAS, CET and LCQ will be completed. Identifying the risk factors for patients with persistent cough by analyzing the demographic information and baseline clinical characteristics including cough duration, comorbidities, accompanying symptoms, airway inflammation biomarkers and treatment situations during the follow-up period, etc.

3. Identifing phenotypes and endotypes, based on biomarkers and/or clinical parameters.

   Time frame: After baseline entry and At the first or second year follow-up

   To elucidate the potential phenotypes and endotypes of chronic cough, demographics, baseline clinical characteristics including cough duration, cough triggers, cough timing, cough complications and associated symptoms, comorbidities etc., cough severity evaluated by cough VAS, urge to cough VAS, CET and LCQ and baseline diagnostic tests including lung function, FeNO, blood routine tests will be analyzed. Cough relief status also will be recorded during the annual follow-up. Further more, biological samples including peripheral blood mononuclear cells (PBMC), serum, sputum samples including sputum supernatant, sputum cells and urine were collected from a subset of patients at baseline and at the 1-year follow-up. For some patients with refractory chronic cough, additional biological specimens such as airway mucosa and bronchoalveolar lavage fluid will be collected. These samples will undergo transcriptomics, metagenomics, proteomics, metabolomics, whole exome sequencing, single-cell AT