Differential Clinical Significance of FENO200 and CANO in Asthma, Chronic Obstructive Pulmonary Disease (COPD), and Asthma-COPD Overlap (ACO)

Guansheng Zeng,1,* Jian Xu,1,* Huadong Zeng,1 Cuilan Wang,1 Lichang Chen,2 Huapeng Yu1 1Department of Pulmonary and Critical Care Medicine, Shenzhen Hospital, Southern Medical University, Shenzhen, People’s Republic of China; 2Department of Pulmonary and Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Huapeng Yu, Department of Pulmonary and Critical Care Medicine, Shenzhen Hospital, Southern Medical University, Shenzhen, People’s Republic of China, Email [email protected] Lichang Chen, Department of Pulmonary and Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, People’s Republic of China, Email [email protected]: To investigate the differential clinical significance of fractional concentration of exhaled nitric oxide measured at a flow rate of 200 mL/s (FENO200) and concentration of nitric oxide in alveolar (CANO) in asthma, chronic obstructive pulmonary disease (COPD) or asthma-COPD Overlap (ACO).Methods: A total of 178 patients were included, with 82 patients in asthma group, 47 patients in COPD group and 49 patients in ACO group. Data for demographic data, spirometry and exhaled nitric oxide were collected for comparative analysis, correlation analysis and discriminant canonical analysis.Results: The values of FENO200 in asthma, COPD and ACO groups were 11.0(7.0– 22.3), 8.0(6.0– 11.0) and 9.0(6.5– 19.5) ppb, respectively. In the asthma group, FENO200 exhibited negative correlations with FEV1/FVC, MMEF and MEF50. No significant correlation was observed between CANO and pulmonary function parameters. In the COPD group, both FENO200 and CANO showed negative correlation with pulmonary function parameters including FVC, FEV1, PEF, MMEF, MEF75, MEF50. In the ACO group, FENO200 demonstrated no significant correlation with pulmonary function parameters, while CANO was correlated with FEV1, PEF, MMEF and MEF50. In COPD group, ΔFEV1 in the bronchodilator test was correlated with FENO200. As for the ACO group, ΔFEV1 was correlated with CANO. In the discriminant canonical analysis, four parameters including gender, age, MEF75 and FENO50 discriminated between the three groups of asthma, COPD and ACO.Conclusion: In asthma, COPD and ACO, FENO200 has demonstrated a robust correlation with CANO. Elevated FENO200 levels are predominantly indicative of pulmonary function impairment in asthma and COPD, whereas elevated CANO levels are mainly correlated with pulmonary function impairment in COPD and ACO. Compared with FENO200 and CANO, FENO50 may have a better discriminatory ability in distinguishing asthma, COPD and ACO.Keywords: FENO200, CANO, ACO, asthma, chronic obstructive pulmonary disease