Assessment of clinical application value of FeNO combined with spirometry parameters for predicting airway hyperresponsiveness

<bold>Objective:</bold> To determine the predictive value of fractional exhaled nitric oxide (FeNO) combined with spirometry parameters for bronchial provocation test (BPT) positivity. <bold>Methods:</bold> FeNO, spirometry, and BPT data collected between June 2021 and June 2022 were retrospectively evaluated. Receiver-operating characteristic curves (ROC) for FeNO and spirometry indices were constructed to assess their overall accuracy in predicting AHR. Additionally, multivariable logistic regression models were constructed to predict AHR, and model sensitivity, specificity, and areas under the receiver operating curve (AUCs) were calculated. <bold>Results:</bold> In the training cohort, subjects positive for BPT (n=170) exhibited increased FeNO, and decreased lung ventilation function compared with BPT-negative subjects (n=321) (<italic>P</italic> < 0.001 for all). The PD20 level was negatively correlated with the increase in FeNO₅₀ and FeNO₂₀₀ (r = -0.420 and r = -0.417, <italic>P</italic> < 0.001 both). The AUCs of variables used singly for an AHR diagnosis were lower than 0.798. Joint models of FeNO with lung ventilation function significantly increased the AUCs, compared to univariate AUCs (<italic>P</italic> < 0.001 for all). A combined application of FeNO₅₀, FEV1/FVC, FEV1 % pre, FEV1/FVC % pre, FEV1/VC _MAX % pre, PEF % pre, MEF₇₅ % pre, MEF₅₀ % pre, MEF₂₅ % pre, and MMEF % pre for predicting positive BPT had an AUC of 0.920. In the validation cohort, the combination of these ten variables yielded a specificity of 76% and a sensitivity of 92%. Furthermore, a website based on the model for predicting positive BPT was developed. <bold>Conclusions:</bold> FeNO combined with spirometry has a high predictive value for positive BPT, and can be usd to assess AHR.