Six-minute walk distance predictors, including CT scan measures, in the COPDGene cohort

Mehdi Rambod; Janos Porszasz; Barry J Make; James D Crapo; Richard Casaburi; COPDGene Investigators

doi:10.1378/chest.11-0870

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Six-minute walk distance predictors, including CT scan measures, in the COPDGene cohort

Journal article

Open access

Peer reviewed

Six-minute walk distance predictors, including CT scan measures, in the COPDGene cohort

Mehdi Rambod, Janos Porszasz, Barry J Make, James D Crapo, Richard Casaburi and COPDGene Investigators

Chest, Vol.141(4), pp.867-875

04/2012

DOI: 10.1378/chest.11-0870

PMCID: PMC3318949

PMID: 21960696

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https://europepmc.org/articles/pmc3318949View

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Abstract

Exercise tolerance in COPD is only moderately well predicted by airflow obstruction assessed by FEV(1). We determined whether other phenotypic characteristics, including CT scan measures, are independent predictors of 6-min walk distance (6MWD) in the COPDGene cohort. COPDGene recruits non-Hispanic Caucasian and African American current and ex-smokers. Phenotyping measures include postbronchodilator FEV(1) % predicted and inspiratory and expiratory CT lung scans. We defined % emphysema as the percentage of lung voxels < -950 Hounsfield units on the inspiratory scan and % gas trapping as the percentage of lung voxels < -856 Hounsfield units on the expiratory scan. Data of the first 2,500 participants of the COPDGene cohort were analyzed. Participant age was 61 ± 9 years; 51% were men; 76% were non-Hispanic Caucasians, and 24% were African Americans. Fifty-six percent had spirometrically defined COPD, with 9.3%, 23.4%, 15.0%, and 8.3% in GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I to IV, respectively. Higher % emphysema and % gas trapping predicted lower 6MWD (P < .001). However, in a given spirometric group, after adjustment for age, sex, race, and BMI, neither % emphysema nor % gas trapping, or their interactions with FEV(1) % predicted, remained a significant 6MWD predictor. In a given spirometric group, only 16% to 27% of the variance in 6MWD could be explained by age, male sex, Caucasian race, and lower BMI as significant predictors of higher 6MWD. In this large cohort of smokers in a given spirometric stage, phenotypic characteristics were only modestly predictive of 6MWD. CT scan measures of emphysema and gas trapping were not predictive of 6MWD after adjustment for other phenotypic characteristics.

Aged

Aged, 80 and over

Emphysema - physiopathology

Exercise Tolerance

Female

Forced Expiratory Volume

Humans

Male

Middle Aged

Pulmonary Disease, Chronic Obstructive - diagnostic imaging

Pulmonary Disease, Chronic Obstructive - physiopathology

Smoking - physiopathology

Spirometry

Time Factors

Tomography, X-Ray Computed

Walking

Details

Title: Subtitle: Six-minute walk distance predictors, including CT scan measures, in the COPDGene cohort
Creators: Mehdi Rambod - Los Angeles Biomedical Research Institute
Janos Porszasz - Los Angeles Biomedical Research Institute
Barry J Make - National Jewish Health
James D Crapo - National Jewish Health
Richard Casaburi - The Lundquist Institute
COPDGene Investigators
Contributors: E Hoffman (Contributor) - University of Iowa, Radiology
Resource Type: Journal article
Publication Details: Chest, Vol.141(4), pp.867-875
DOI: 10.1378/chest.11-0870
PMID: 21960696
PMCID: PMC3318949
NLM abbreviation: Chest
ISSN: 0012-3692
eISSN: 1931-3543
Grant note: U01HL089897 / NHLBI NIH HHS U01 HL089856 / NHLBI NIH HHS U01 HL089897 / NHLBI NIH HHS UL1 TR000005 / NCATS NIH HHS U01HL089856 / NHLBI NIH HHS UL1 RR024153 / NCRR NIH HHS
Language: English
Date published: 04/2012
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
Record Identifier: 9984318791102771

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