Associations Between Muscle Weakness and Clinical Outcomes in Current and Former Smokers

Richard H Zou; S Mehdi Nouraie; Harry B Rossiter; Merry-Lynn McDonald; Dawn L DeMeo; Stefanie Mason; George R Washko; Punam K Saha; Barry J Make; Richard Casaburi; Elizabeth A Regan; Jessica Bon; COPDGene Investigators

doi:10.15326/jcopdf.2022.0365

Associations Between Muscle Weakness and Clinical Outcomes in Current and Former Smokers

Chronic Obstr Pulm Dis. 2023 Jan 25;10(1):112-121. doi: 10.15326/jcopdf.2022.0365.

Authors

Affiliations

¹ Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States.
² The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States.
³ Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
⁴ Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States.
⁵ Department of Radiology, University of Iowa, Iowa City, Iowa, United States.
⁶ Department of Medicine, National Jewish Health, Denver, Colorado, United States.
⁷ Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States.

Abstract

Introduction: Smokers with chronic obstructive pulmonary disease (COPD) are at increased risk of muscle weakness. There are limited data describing weakness in smokers with normal spirometry and preserved ratio-impaired spirometry (PRISm), 2 subgroups at risk of respiratory symptom burden and activity limitations. In this study, we evaluated the associations of 2 weakness measures, sit-to-stand (STS) and handgrip strength (HGS), with clinical outcomes in smokers with COPD, normal spirometry, and PRISm.

Methods: We evaluated 1972 current and former smokers from the COPD Genetic Epidemiology (COPDGene^®) cohort with STS and HGS measurements at their 10-year study visit. Multivariable regression modeling was used to assess associations between weakness measures and the 6-minute walk distance (6MWD) test, the St George's Respiratory Questionnaire (SGRQ), the Short-Form-36 (SF-36), severe exacerbations, and prospective mortality, reported as standardized coefficients (β), odds ratios (ORs), or hazard ratios (HRs).

Results: Compared with HGS, STS was more strongly associated with the 6MWD (β=0.45, p<0.001 versus. β=0.25, p<0.001), SGRQ (β=-0.24, p<0.001 versus β=-0.18, p<0.001), SF-36 Physical Functioning (β=0.36, p<0.001 versus β=0.25, p<0.001), severe exacerbations (OR 0.95, p=0.04 versus OR 0.97, p=0.01), and prospective mortality (HR 0.83, p=0.001 versus HR 0.94, p=0.03). Correlations remained after stratification by spirometric subgroups. Compared with males, females had larger magnitude effect sizes between STS and clinical outcomes.

Conclusions: STS and HGS are easy to perform weakness measures that provide important information about functional performance, health-related quality of life, severe exacerbations, and survival in smokers, regardless of spirometric subgroup. This iterates the importance of screening current and former smokers for weakness in the outpatient setting.

Keywords: COPD outcomes; COPDGene; chronic obstructive pulmonary disease; cigarette smoking; musculoskeletal comorbidities.

Abstract

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