Original Article
FEF25-75% Is a More Sensitive Measure Reflecting Airway Dysfunction in Patients with Asthma: A Comparison Study Using FEF25-75% and FEV1%

https://doi.org/10.1016/j.jaip.2021.06.027Get rights and content

Background

Reduced forced expiratory flow between 25% and 75% of vital capacity percent predicted (FEF25-75%) representing small airway dysfunction (SAD) was associated with asthma development and progression.

Objective

To investigate whether FEF25-75% was superior to forced expiratory volume in 1 second in predicted (FEV1%) in reflecting asthma features in adult patients.

Methods

A retrospective spirometry dataset comprising 1801 adult patients with confirmed asthma and a subgroup of 332 patients having detailed clinical data were used to explore the association of FEF25-75% and/or FEV1% with clinical features of asthma.

Results

Of the 1801 subjects, FEV1% and FEF25-75% ranged from 136.8% to 10.2% and 127.3% to 3.1%, respectively. FEF25-75% < 65% was present in 1,478 (82.07%) of patients. FEF25-75% was strongly correlated with matched FEV1% (r = 0.900, P < .001). FEF25-75% and FEV1% were both correlated with airway hyperresponsiveness (r = 0.436, P < .001; r = 0.367, P < .001), asthma control test score (r = 0.329, P < .001; r = 0.335, P < .001), and sputum eosinophil count (r = −0.306, P < .001; r = −0.307, P < .001). Receiver-operating characteristic curves showed that FEF25-75% had greater value in predicting severe asthma (area under the curve: 0.84 vs 0.81, P = .018), airflow obstruction (0.97 vs 0.89, P < .001), and severe bronchial hyperresponsiveness (0.74 vs 0.69, P = .012) as compared with FEV1%. Patients with SAD (FEF25-75% < 65%) in the presence of normal FEV1% exhibited higher sputum eosinophil counts and had an increased dosage of daily inhaled corticosteroids (P < .001 and P = .010) than patients with normal lung function and their FEF25-75% values correlated with sputum eosinophil count (r = −0.419, P = .015), but not FEV1%.

Conclusion

FEF25-75% represented small airway function and was more sensitive at reflecting airway hyperresponsiveness, inflammation, and disease severity as compared with FEV1% in patients with asthma. Our data suggest further assessment of FEF25-75% in asthma management, particularly for those with SAD who present normal FEV1%.

Section snippets

Patients

We screened data from adult patients aged between 18 and 65 years with a diagnosis of asthma who have performed lung function tests for baseline assessment or routine follow-up for clinical treatment at the Spirometry Department at the First Affiliated Hospital of Guangzhou Medical University from 2017 to 2019. Patients with asthma were confirmed by a history of variable respiratory symptoms, including wheezing, shortness of breath, chest tightness, and cough, as well as objective evidence of a

Patients

After screening data including a total of 9,677 results from the electronic database of the Department of Spirometry Laboratory of the First Affiliated Hospital of Guangzhou Medical University from 2017 to 2019, 1801 adult patients with confirmed asthma met our inclusive criteria. The spirometry results of these individuals underwent analysis (Figure 1). Among the cohort, 902 (50.08%), 333 (18.49%), 209 (11.60%), 124 (6.89%), 148 (8.22%), and 85 (4.72%) individuals had FEV1 ≥ 80%, 70%-79%,

Discussion

Our study is, to the best of our knowledge, the first study to compare the difference between FEF25-75% and FEV1% with respect to their associations with clinical characteristics in adult asthmatic patients with a broad range of lung function impairments. The main findings were as follows: (1) FEF25-75% was strongly correlated with FEV1%; (2) FEF25-75% and FEV1% showed similar clinical relevance, but FEF25-75% had a stronger correlated level with airway hyperresponsiveness and was more

Acknowledgments

We thank LetPub (www.letpub.com) for its linguistic assistance and scientific consultation during the preparation of this manuscript.

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      Each value, which consisted of the best of 3 reproducible measurements, was expressed as a percentage of predicted computed using the equations of Quanjer and Stocks.21,22 Small-airway dysfunction was judged as FEF25%-75% values less than 65% of predicted.23 Lung hyperinflation was suggested by RV values greater than 120% of predicted and RV/TLC ratio greater than 30%.22

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    This work was supported by a Precision Medicine Research grant from the National Key Research and Development Plan of China (grant no. 2016YFC0905800), the Breeding Program of the Major Research Plan (9154204) of the National Natural Science Foundation of China, and the Key Project of the National Natural Science Foundation of China-Guangdong United Fund (U1801286) and special funding for science and technology development from Guangdong province (Frontier and key technology innovation direction—major science and technology special project) (2017B020226006).

    Conflicts of interest: The authors declare that they have no relevant conflicts of interest.

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