Extract
We thank F. Trinkmann and co-authors for their appreciation of our work and also in raising important questions on the role of small airway function in early detection of lung function impairment associated with asthma and smoking, leading to development of COPD 1]. The focus of our study was not simply on small airway function but rather, the onset and trajectories of lung function impairment associated with asthma and smoking. However, we agree that small airway function is an important part of that assessment. The authors raise two important points in this regard. First, that (at a microscopic level) significant pathology is present in the small airways before it can be detected by commonly used diagnostic tests, and secondly that other tests such as oscillometry, static lung volumes, transfer factor and radiological imaging add to the assessment of small airway function. We agree with both these points. However, we disagree with their assertion that assessment of small airway function using spirometry, and more specifically, forced expiratory flow at 25–75% of forced vital capacity (FEF25–75) is neither useful nor sensitive [2].
Abstract
Both impulse oscillometry and spirometry provide comparable information for small to mid-airway function. However, spirometry is more sensitive in detecting bronchodilator reversibility. https://bit.ly/2XyQ0Sa
Acknowledgement
We would like to acknowledge the help of all the staff at The David Hide Asthma and Allergy Research Centre in undertaking the assessments of the Isle of Wight birth cohort and, specifically, Stephen Potter for helping with lung function data quality checks and preparation of the high quality figure.
Footnotes
Conflict of interest: S.H. Arshad has nothing to disclose.
Conflict of interest: R. Kurukulaaratchy has nothing to disclose.
Conflict of interest: H. Zhang has nothing to disclose.
Conflict of interest: C. Hodgekiss has nothing to disclose.
Conflict of interest: W. Karmaus has nothing to disclose.
Conflict of interest: J.W. Holloway has nothing to disclose.
Conflict of interest: G. Roberts has nothing to disclose.
Support statement: The Isle of Wight Birth Cohort assessments have been supported by the National Institutes of Health USA (grant number R01 HL082925), Asthma UK (grant number 364) and the David Hide Asthma and Allergy Research Trust. Funding information for this article has been deposited with the Crossref Funder Registry.
- Received May 22, 2020.
- Accepted May 23, 2020.
- Copyright ©ERS 2020