The Value of Fractional Exhaled Nitric Oxide and Forced Mid-Expiratory Flow as Predictive Markers of Bronchial Hyperresponsiveness in Adults with Chronic Cough

Value of Exhaled Nitric Oxide and FEF25–75 in Identifying Factors Associated With Chronic Cough in Allergic Rhinitis

“…The ROC results showed that FEF 25–75 was more accurate than FEV1 in diagnosing CVA. In keeping with a previous study on Chinese population with chronic cough, which showed that FEF 25–75 < 78.5% strongly predicted positive AHR,42 we showed that a cutoff value of FEF 25–75 at 74.6% (slightly lower than the research mentioned above, which may be attributed to the atopic nature of the enrolled population in our study) exhibited good diagnostic sensitivity, specificity, NPV, and PPV for CVA in both chronic cough and CVA/NAEB groups. Based on these results, we propose that FEF 25–75 values less than 75% may indicate CVA as a potential cause of chronic cough in patients with AR.…”

“…A level of FeNO at 43.5 ppb in the current study was also found to have the best ability to identify patients with CVA; with a sensitivity of 75.6%, specificity of 86.6%, PPV of 64.8%, and NPV of 91.6%. In line with this finding, a recently released study has shown that FeNO levels > 43 ppb could predict positive AHR ( i.e ., CVA) in Chinese patients with chronic cough 42. Collectively, these studies suggest that FeNO is a reasonable indicator for initially diagnosing CVA/NAEB in AR patients with chronic cough.…”

The value of small airway function parameters and fractional exhaled nitric oxide for predicting positive methacholine challenge test in asthmatics of different ages with FEV1 ≥ 80% predicted

“…Additionally, eosinophilic inflammation identified through fractional exhaled nitric oxide (FeNO) is also associated with the pathophysiological process of asthma 12 . A previous study reported that the area under the curve (AUC) of the combination of forced expiratory flow (FEF) between 25% and 75% (FEF 25%–75% ) and FeNO for predicting AHR presence in patients with cough‐variant asthma was significantly higher than that of the parameters being applied separately (all p < 0.05); furthermore, FeNO >43 ppb and FEF 25%–75% <78.5% were the optimal cutoff values 11 . Therefore, SAFPs combined with FeNO can improve the predictive value for AHR presence in asthma diagnosis 11 .…”

“…A previous study reported that the area under the curve (AUC) of the combination of forced expiratory flow (FEF) between 25% and 75% (FEF 25%–75% ) and FeNO for predicting AHR presence in patients with cough‐variant asthma was significantly higher than that of the parameters being applied separately (all p < 0.05); furthermore, FeNO >43 ppb and FEF 25%–75% <78.5% were the optimal cutoff values 11 . Therefore, SAFPs combined with FeNO can improve the predictive value for AHR presence in asthma diagnosis 11 . Further, compared with MCT, SAFP, and FeNO measurement are more accessible, safer, cheaper ($5–10 lower), and time‐saving (15–20 min).…”

“…In the diseased state, pulmonary function changes are not detected by standard spirometry until approximately 75% of the small airways are obstructed 9,10 . Therefore, it is crucial for predicting AHR presence in patients with a normal FEV 1 for early stage asthma diagnosis based on small airway function parameters (SAFPs) 11 . Additionally, eosinophilic inflammation identified through fractional exhaled nitric oxide (FeNO) is also associated with the pathophysiological process of asthma 12 .…”