Novel Respiratory Disability Score Predicts COPD Exacerbations and Mortality in the SPIROMICS Cohort

Abstract

Rationale

Some COPD patients develop extreme breathlessness, decreased exercise capacity and poor health status yet respiratory disability is poorly characterized as a distinct phenotype.

Objective

To define respiratory disability in COPD based on available functional measures and to determine associations with risk for exacerbations and death.

Methods

We analyzed baseline data from a multi-center observational study (SPIROMICS). This analysis includes 2332 participants (472 with severe COPD, 991 with mild/moderate COPD, 726 smokers without airflow obstruction and 143 non-smoking controls).

Measurements

We defined respiratory disability by ≥4 of 7 criteria: mMRC dyspnea scale ≥3; Veterans Specific Activity Questionnaire <5; 6-minute walking distance <250 m; St George’s Respiratory Questionnaire activity domain >60; COPD Assessment Test >20; fatigue (FACIT-F Trial Outcome Index) <50; SF-12 <20.

Results

Using these criteria, respiratory disability was identified in 315 (13.5%) participants (52.1% female). Frequencies were severe COPD 34.5%; mild-moderate COPD 11.2%; smokers without obstruction 5.2% and never-smokers 2.1%. Compared with others, participants with disability had more emphysema (13.2 vs. 6.6%) and air-trapping (37.0 vs. 21.6%) on HRCT (P<0.0001). Using principal components analysis to derive a disability score, two factors explained 71% of variance, and a cut point −1.0 reliably identified disability. This disability score independently predicted future exacerbations (ß=0.34; CI 0.12, 0.64; P=0.003) and death (HR 2.97; CI 1.54, 5.75; P=0.001). Thus, participants with disability by this criterion had almost three times greater mortality compared to those without disability.

Conclusion

Our novel SPIROMICS respiratory disability score in COPD was associated with worse airflow obstruction as well as airway wall thickening, lung parenchymal destruction and certain inflammatory biomarkers. The disability score also proved to be an independent predictor of future exacerbations and death. These findings validate disability as an important phenotype in the spectrum of COPD.

Journal

Journal ID (nlm-ta): Int J Chron Obstruct Pulmon Dis

Journal ID (iso-abbrev): Int J Chron Obstruct Pulmon Dis

Journal ID (publisher-id): COPD

Journal ID (pmc): copd

Title: International Journal of Chronic Obstructive Pulmonary Disease

Publisher: Dove

ISSN (Print): 1176-9106

ISSN (Electronic): 1178-2005

Publication date (Electronic): 04 August 2020

Publication date Collection: 2020

Volume: 15

Pages: 1887-1898

Affiliations

[1 ]Departments of Medicine and Physiology, David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA, USA

[2 ]Section of Pulmonary and Critical Care Medicine, Department of Veterans Affairs Medical Center, University of Utah , Salt Lake City, UT, USA

[3 ]Pulmonary and Critical Care Medicine Division, Department of Internal Medicine, University of Michigan Health System , Ann Arbor, MI, USA

[4 ]Veterans Affairs Ann Arbor Healthcare System , Ann Arbor, MI, USA

[5 ]National Jewish Health, University of Colorado School of Medicine , Denver, CO, USA

[6 ]University of North Carolina Marisco Lung Institute , Chapel Hill, NC, USA

[7 ]Department of Radiology, University of Iowa , Iowa City, IA, USA

[8 ]Department of Pulmonary and Critical Care Medicine, Temple University , Philadelphia, PA, USA

[9 ]Department of Medicine, University of Alabama at Birmingham , Birmingham, AL, USA

[10 ]Johns Hopkins University School of Medicine , Baltimore, MD, USA

[11 ]Department of Medicine, University of Illinois at Chicago , Chicago, IL, USA

[12 ]Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California San Francisco , San Francisco, CA, USA

[13 ]Wake Forest School of Medicine , Winston-Salem, NC, USA

[14 ]Department of Medicine, Columbia University Medical Center , New York, NY, USA

[15 ]Joan and Sanford I Weill Department of Medicine, Division of Pulmonary and Critical Care Medicine, Weill Cornell Medicine , New York, NY, USA

Author notes

Correspondence: Christopher B Cooper Departments of Medicine and Physiology,David Geffen School of Medicine,University of California Los Angeles ,10833 Le Conte Avenue, 37-131 CHS, Los Angeles, CA90095, USA Email [e-mail]

Article

Publisher ID: 250191

DOI: 10.2147/COPD.S250191

PMC ID: 7417644

Copyright statement: © 2020 Cooper et al.

License:

This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License ( http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms ( https://www.dovepress.com/terms.php).

Page count

Figures: 2, Tables: 3, References: 24, Pages: 12

Funding

SPIROMICS was supported by contracts from the NIH/NHLBI (HHSN268200900013C, HHSN268200900014C, HHSN268200900015C, HHSN268200900016C, HSN268200900017C, HHSN268200900018C, HHSN268200900019C, HHSN268200900020C), grants from the NIH/NHLBI (U01 HL137880 and U24 HL141762), and supplemented by contributions made through the Foundation for the NIH and the COPD Foundation from AstraZeneca/MedImmune; Bayer; Bellerophon Therapeutics; Boehringer-Ingelheim Pharmaceuticals, Inc.; Chiesi Farmaceutici S.p.A.; Forest Research Institute, Inc.; GlaxoSmithKline; Grifols Therapeutics, Inc.; Ikaria, Inc.; Novartis Pharmaceuticals Corporation; Nycomed GmbH; ProterixBio; Regeneron Pharmaceuticals, Inc.; Sanofi; Sunovion; Takeda Pharmaceutical Company; and Theravance Biopharma and Mylan.

Categories

Subject: Original Research