• Fang Yi, Ruchong Chen, Wei Luo, Danyuan Xu, Lina Han, Baojuan Liu, Siqi Jiang, Qiaoli Chen, and Kefang Lai.
• State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, P.R. China.
• Chest. 2016 Apr 1; 149 (4): 1042-51.

BackgroundWhether fractional exhaled nitric oxide (FeNO) measurement alone or combined with sputum eosinophil and atopy is useful in predicting corticosteroid-responsive cough (CRC) and non-CRC (NCRC) is not clear.MethodsA total of 244 patients with chronic cough and 59 healthy subjects as control were enrolled. The causes of chronic cough were confirmed according to a well-established diagnostic algorithm. FeNO measurement and induced sputum for differential cell were performed in all subjects.ResultsCRC occurred in 139 (57.0%) patients and NCRC occurred in 105. The FeNO level in CRC significantly correlated with sputum eosinophils (rs = 0.583, P < .01). The median (quarter) of FeNO level in CRC was significantly higher than NCRC (32.0 ppb [19.0-65.0 ppb] vs 15.0 ppb [11.0-22.0 ppb], P < .01). FeNO of 31.5 ppb had a sensitivity and specificity of 54.0% and 91.4%, respectively, in predicting CRC from chronic cough, with a positive predictive value of 89.3% and a negative predictive value of 60.0%. If the patients had a combination of low level of FeNO ( < 22.5 ppb), normal sputum eosinophil ( < 2.5%), and absence of atopy, the sensitivity and specificity would be 30.3% and 93.5% for predicting NCRC.ConclusionsIn our cohort, a high level (≥ 31.5 ppb) of FeNO indicates more likelihood of CRC, but the sensitivity is insufficient to rule out a diagnosis of CRC. A combination of low-level FeNO, normal sputum eosinophil, and absence of atopy suggests a lower likelihood of CRC.Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

40 keywords...

hide…