Muscle strength, muscle mass, and physical disability in women with systemic lupus erythematosus

James S. Andrews, Laura Trupin, Gabriela Schmajuk, Jennifer Barton, Mary Margaretten, Jinoos Yazdany, Edward H. Yelin, Patricia P. Katz

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Objective: Data describing relationships between muscle strength, muscle mass, and physical disability among individuals with systemic lupus erythematosus (SLE) are limited. The present study examines the relationship of muscle strength and muscle mass with physical disability among adult women with SLE.

Methods: A total of 146 women from a longitudinal SLE cohort participated in the study. All measures were collected during an in-person research visit. Lower extremity muscle strength was assessed by peak knee torque of extension and flexion and by chair-stand time. Total lean body mass, appendicular lean mass, and fat mass (kg/m2) were measured by whole-body dual x-ray absorptiometry. Self-reported physical disability was assessed using the Short Form 36 health survey (SF-36) physical functioning subscale, and the Valued Life Activities (VLA) disability scale. Spearman's rank correlation coefficients tested the correlations between muscle strength, muscle mass, and disability scores. Regression analyses modeled the effect of lower extremity muscle strength and mass on SF-36 and VLA disability scores controlling for age, SLE duration, SLE disease activity measured with the Systemic Lupus Activity Questionnaire, physical activity level, prednisone use, body composition, and depression.

Results: On all measures, reduced lower extremity muscle strength was associated with poorer SF-36 and VLA disability scores. Trends persisted after adjustment for covariates. Muscle mass was moderately correlated with muscle strength, but did not contribute significantly to adjusted regression models.

Conclusion: Lower extremity muscle strength, but not muscle mass, was strongly associated with physical disability scores. While further studies are needed, these findings suggest that improving muscle strength may reduce physical disability among women with SLE.

Original languageEnglish (US)
Pages (from-to)120-127
Number of pages8
JournalArthritis Care and Research
Volume67
Issue number1
DOIs
StatePublished - Jan 1 2015

ASJC Scopus subject areas

  • Rheumatology

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    Andrews, J. S., Trupin, L., Schmajuk, G., Barton, J., Margaretten, M., Yazdany, J., Yelin, E. H., & Katz, P. P. (2015). Muscle strength, muscle mass, and physical disability in women with systemic lupus erythematosus. Arthritis Care and Research, 67(1), 120-127. https://doi.org/10.1002/acr.22399