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Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies. II. The Childhood Myositis Assessment Scale (CMAS): a quantitative tool for the evaluation of muscle function. The Juvenile Dermatomyositis Disease Activity Collaborative Study Group.

Publication ,  Journal Article
Lovell, DJ; Lindsley, CB; Rennebohm, RM; Ballinger, SH; Bowyer, SL; Giannini, EH; Hicks, JE; Levinson, JE; Mier, R; Pachman, LM; Passo, MH ...
Published in: Arthritis Rheum
October 1999

OBJECTIVE: To develop, validate, and determine the measurement characteristics of a quantitative tool for assessing the severity of muscle involvement in children with idiopathic inflammatory myopathies. METHODS: The Childhood Myositis Assessment Scale (CMAS) was developed from 2 existing observational functional assessment tools to assess muscle function in the areas of strength and endurance across a wide range of ability and ages. The 14 ordinal items included were chosen to assess primarily axial and proximal muscle groups and are ranked with standard performance and scoring methods. Following the development of the CMAS, a training video and written instructions were developed and reviewed by the physicians participating in this study. Subsequently, utilizing a randomized block design, 12 physicians independently scored 10 children (9 with dermatomyositis, 1 with polymyositis; ages 4-15 years) twice in one day (morning and afternoon) on the CMAS. A pediatric physical therapist performed quantitative manual muscle strength testing (MMT) twice on each child (morning and afternoon), including the neck, trunk, and proximal and distal extremity muscle groups. RESULTS: The CMAS has a potential range of 0-51, with higher scores indicating greater muscle strength and endurance. The observed mean for the 10 patients was 36.4 (median 44, SD 14.1, observed range 5-51). The total score for the CMAS correlated with the physician's global assessment (by visual analog scale) of disease activity, the MMT score, serum creatine kinase level, and the Juvenile Arthritis Functional Assessment Report score. The score on the CMAS was not correlated with patient age. Interrater reliability (Kendall's coefficient of concordance) ranged from 0.77 to 1.0 for individual items (all P < 0.001), and overall, it was 0.95 (P < 0.001). Intrarater reliability for the individual physicians was measured by correlation of the CMAS scores for each patient on 2 separate evaluations and ranged from 0.97 to 0.99, with an overall correlation for all physicians of 0.98 (all P < 0.001). CONCLUSION: The CMAS demonstrated an acceptable range of observed scores, excellent convergent validity, and excellent inter- and intrarater reliability. The CMAS is validated to quantitatively assess muscle function in the areas of strength and endurance in children with idiopathic inflammatory myopathies. It can be used in routine clinical care as well as therapeutic trials.

Duke Scholars

Published In

Arthritis Rheum

DOI

ISSN

0004-3591

Publication Date

October 1999

Volume

42

Issue

10

Start / End Page

2213 / 2219

Location

United States

Related Subject Headings

  • Myositis
  • Humans
  • Child, Preschool
  • Child
  • Arthritis & Rheumatology
  • Adolescent
  • 1117 Public Health and Health Services
  • 1107 Immunology
  • 1103 Clinical Sciences
 

Citation

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Lovell, D. J., Lindsley, C. B., Rennebohm, R. M., Ballinger, S. H., Bowyer, S. L., Giannini, E. H., … Rider, L. G. (1999). Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies. II. The Childhood Myositis Assessment Scale (CMAS): a quantitative tool for the evaluation of muscle function. The Juvenile Dermatomyositis Disease Activity Collaborative Study Group. Arthritis Rheum, 42(10), 2213–2219. https://doi.org/10.1002/1529-0131(199910)42:10<2213::AID-ANR25>3.0.CO;2-8
Lovell, D. J., C. B. Lindsley, R. M. Rennebohm, S. H. Ballinger, S. L. Bowyer, E. H. Giannini, J. E. Hicks, et al. “Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies. II. The Childhood Myositis Assessment Scale (CMAS): a quantitative tool for the evaluation of muscle function. The Juvenile Dermatomyositis Disease Activity Collaborative Study Group.Arthritis Rheum 42, no. 10 (October 1999): 2213–19. https://doi.org/10.1002/1529-0131(199910)42:10<2213::AID-ANR25>3.0.CO;2-8.
Lovell DJ, Lindsley CB, Rennebohm RM, Ballinger SH, Bowyer SL, Giannini EH, Hicks JE, Levinson JE, Mier R, Pachman LM, Passo MH, Perez MD, Reed AM, Schikler KN, Smith M, Zemel LS, Rider LG. Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies. II. The Childhood Myositis Assessment Scale (CMAS): a quantitative tool for the evaluation of muscle function. The Juvenile Dermatomyositis Disease Activity Collaborative Study Group. Arthritis Rheum. 1999 Oct;42(10):2213–2219.
Journal cover image

Published In

Arthritis Rheum

DOI

ISSN

0004-3591

Publication Date

October 1999

Volume

42

Issue

10

Start / End Page

2213 / 2219

Location

United States

Related Subject Headings

  • Myositis
  • Humans
  • Child, Preschool
  • Child
  • Arthritis & Rheumatology
  • Adolescent
  • 1117 Public Health and Health Services
  • 1107 Immunology
  • 1103 Clinical Sciences