The Value of FENO Measurement for Predicting Treatment Response in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

Background: Fractional exhaled nitric oxide (FENO) has been shown to be a marker of airway inflammation in various pulmonary diseases, including chronic obstructive pulmonary disease (COPD). In this study, we assessed the FENO level in patients with acute exacerbations of COPD (AECOPD) and analyzed the predictive value of the FENO level for treatment response. Methods: Demographic data were collected at admission. FENO, lung function, blood gases, COPD Assessment Test (CAT), and modified Medical Research Council (mMRC) scores were measured at admission and on day 7. At the second visit, the patients were asked to report their health status; scores ranged from 1 to 5, representing "much better", "slightly better", "no change", "slightly worse", and "much worse", respectively. The treatment response was evaluated based on the patient's reported health status (responders were those who reported much better and slightly better) and lung function (responders were those who presented an increase in FEV Results: A total of 182 patients were recruited into the analysis. The FENO level positively correlated with an increase in FEV Conclusion: FENO levels, determined at hospital admission, are potential to predict the overall treatment response in AECOPD patients, including remission in subjective patient-reported health statuses and, also, improvements in lung function. Registry Number: ChiCTR-ROC-16,009,087 (http://www.chictr.org.cn/).