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Forced Expiratory Flow at 25%-75% Links COPD Physiology to Emphysema and Disease Severity in the SPIROMICS Cohort
Journal article   Open access   Peer reviewed

Forced Expiratory Flow at 25%-75% Links COPD Physiology to Emphysema and Disease Severity in the SPIROMICS Cohort

Bonnie E. Ronish, David J. Couper, Igor Z. Barjaktarevic, Christopher B. Cooper, Richard E. Kanner, Cheryl S. Pirozzi, Victor Kim, James M. Wells, MeiLan K. Han, Prescott G. Woodruff, …
Chronic obstructive pulmonary diseases, Vol.9(2), pp.111-121
02/02/2022
DOI: 10.15326/jcopdf.2021.0241
PMCID: PMC9166328
PMID: 35114743
url
https://doi.org/10.15326/jcopdf.2021.0241View
Published (Version of record) Open Access

Abstract

Background: Forced expiratory volume in 1 second (FEV 1 ) is central to the diagnosis of chronic obstructive pulmonary disease (COPD) but is imprecise in classifying disease burden. We examined the potential of the maximal mid-expiratory flow rate (forced expiratory flow rate between 25% and 75% [FEF 25%-75% ]) as an additional tool for characterizing pathophysiology in COPD. Objective: To determine whether FEF 25%-75% helps predict clinical and radiographic abnormalities in COPD. Study Design and Methods: The SubPopulations and InteRediate Outcome Measures In COPD Study (SPIROMICS) enrolled a prospective cohort of 2978 nonsmokers and ever-smokers, with and without COPD, to identify phenotypes and intermediate markers of disease progression. We used baseline data from 2771 ever-smokers from the SPIROMICS cohort to identify associations between percent predicted FEF 25%-75% (%predFEF 25%-75% ) and both clinical markers and computed tomography (CT) findings of smoking-related lung disease. Results: Lower %predFEF 25-75% was associated with more severe disease, manifested radiographically by increased functional small airways disease, emphysema (most notably with homogeneous distribution), CT-measured residual volume, total lung capacity (TLC), and airway wall thickness, and clinically by increased symptoms, decreased 6-minute walk distance, and increased bronchodilator responsiveness (BDR). A lower %predFEF 25-75% remained significantly associated with increased emphysema, functional small airways disease, TLC, and BDR after adjustment for FEV 1 or forced vital capacity (FVC). Interpretation: The %predFEF 25-75% provides additional information about disease manifestation beyond FEV 1 . These associations may reflect loss of elastic recoil and air trapping from emphysema and intrinsic small airways disease. Thus, %predFEF 25-75% helps link the anatomic pathology and deranged physiology of COPD.
emphysema FEF25-75 functional small airways disease mid-flow rate Origianl Research pulmonary physiology spirometry

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