Johns, DP and Das, A and Toelle, BG and Abramson, MJ and Marks, GB and Wood-Baker, R and Walters, EH, Improved spirometric detection of small airway narrowing: concavity in the expiratory flow-volume curve in people aged over 40 years, COPD: journal of chronic obstructive pulmonary disease, 12 pp. 3567-3577. ISSN 1541-2555 (2017) [Refereed Article]
Copyright 2017 Johns et al. Licensed under Creative Commons Attribution-NonCommercial 3.0 Unported (CC BY-NC 3.0) https://creativecommons.org/licenses/by-nc/3.0/
Background and objective: We have explored whether assessing the degree of concavity in the descending limb of the maximum expiratory flow–volume curve enhanced spirometric detection of early small airway disease.
Methods: We used spirometry records from 890 individuals aged $40 years (mean 59 years), recruited for the Burden of Obstructive Lung Disease Australia study. Central and peripheral concavity indices were developed from forced expired flows at 50% and 75% of the forced vital capacity, respectively, using an ideal line joining peak flow to zero flow.
Results: From the 268 subjects classified as normal never smokers, mean values for postbronchodilator central concavity were 18.6% in males and 9.1% in females and those for peripheral concavity were 50.5% in males and 52.4% in females. There were moderately strong correlations between concavity and forced expired ratio (forced expiratory volume in 1 second/ forced vital capacity) and mid-flow rate (forced expiratory flow between 25% and 75% of the FVC [FEF25%–75%]; r=-0.70 to -0.79). The additional number of individuals detected as abnormal using the concavity indices was substantial, especially compared with FEF25%–75%M, where it was approximately doubled. Concavity was more specific for symptoms.
Conclusion: The inclusion of these concavity measures in the routine reports of spirometry would add information on small airway obstruction at no extra cost, time, or effort.
|Item Type:||Refereed Article|
|Keywords:||early airway disease, airflow obstruction, COPD|
|Research Division:||Medical and Health Sciences|
|Research Group:||Cardiorespiratory Medicine and Haematology|
|Research Field:||Respiratory Diseases|
|Objective Group:||Clinical Health (Organs, Diseases and Abnormal Conditions)|
|Objective Field:||Respiratory System and Diseases (incl. Asthma)|
|UTAS Author:||Johns, DP (Associate Professor David Johns)|
|UTAS Author:||Das, A (Dr Aruneema Das)|
|UTAS Author:||Wood-Baker, R (Professor Richard Wood-Baker)|
|UTAS Author:||Walters, EH (Professor Haydn Walters)|
|Web of Science® Times Cited:||2|
|Downloads:||31 View Download Statistics|
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