[History of atopy reduces predictive value of fractional exhaled nitric oxide for eosinophilic airway inflammation in chronic cough].

OBJECTIVE: To investigate the impact of a history of atopy on the value of fractional exhaled nitric oxide (FENO) for predicting sputum eosinophils in patients with chronic cough. METHODS: A total of 868 patients with persistent cough lasting more than 3 weeks without pulmonary infection were enrolled, including 119 patients with subacute cough (defined as cough lasting 3-8 weeks) and 749 with chronic cough (longer than 8 weeks). The predictive value of FENO level for sputum eosinophilia was analyzed using receiver-operating characteristic (ROC) curve analysis, and the area under the curve (AUC) was calculated. The atopy status of the patients was determined by screening for history of allergy, hay fever, or animal or food allergies. RESULTS: 28.5 ppb). CONCLUSION: A history of atopy reduces the predictive value of FENO level for EAI in patients with chronic cough, suggesting the importance of examining the atopic status when interpreting test results of FENO.