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Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies.

Publication ,  Journal Article
Huber, AM; Feldman, BM; Rennebohm, RM; Hicks, JE; Lindsley, CB; Perez, MD; Zemel, LS; Wallace, CA; Ballinger, SH; Passo, MH; Reed, AM ...
Published in: Arthritis Rheum
May 2004

OBJECTIVE: To examine the measurement characteristics of the Childhood Myositis Assessment Scale (CMAS) in children with juvenile idiopathic inflammatory myopathy (juvenile IIM), and to obtain preliminary data on the clinical significance of CMAS scores. METHODS: One hundred eight children with juvenile IIM were evaluated on 2 occasions, 7-9 months apart, using various measures of physical function, strength, and disease activity. Interrater reliability, construct validity, and responsiveness of the CMAS were examined. The minimum clinically important difference (MID) and CMAS scores corresponding to various degrees of physical disability were estimated. RESULTS: The intraclass correlation coefficient for 26 patients assessed by 2 examiners was 0.89, indicating very good interrater reliability. The CMAS score correlated highly with the Childhood Health Assessment Questionnaire (C-HAQ) score and with findings on manual muscle testing (MMT) (r(s) = -0.73 and 0.73, respectively) and moderately with physician-assessed global disease activity and skin activity, parent-assessed global disease severity, and muscle magnetic resonance imaging (r(s) = -0.44 to -0.61), thereby demonstrating good construct validity. The standardized response mean was 0.81 (95% confidence interval 0.53, 1.09) in patients with at least 0.8 cm improvement on a 10-cm visual analog scale for physician-assessed global disease activity, indicating strong responsiveness. In bivariate regression models predicting physician-assessed global disease activity, MMT remained significant in models containing the CMAS (P = 0.03) while the C-HAQ did not (P = 0.4). Estimates of the MID ranged from 1.5 to 3.0 points on a 0-52-point scale. CMAS scores corresponding to no, mild, mild-to-moderate, and moderate physical disability, respectively, were 48, 45, 39, and 30. CONCLUSION: The CMAS exhibits good reliability, construct validity, and responsiveness, and is therefore a valid instrument for the assessment of physical function, muscle strength, and endurance in children with juvenile IIM. Preliminary data on MID and corresponding levels of disability should aid in the clinical interpretation of CMAS scores when assessing patients with juvenile IIM.

Duke Scholars

Published In

Arthritis Rheum

DOI

ISSN

0004-3591

Publication Date

May 2004

Volume

50

Issue

5

Start / End Page

1595 / 1603

Location

United States

Related Subject Headings

  • Severity of Illness Index
  • Reproducibility of Results
  • Predictive Value of Tests
  • Outcome Assessment, Health Care
  • Observer Variation
  • Myositis
  • Motor Activity
  • Humans
  • Disability Evaluation
  • Child, Preschool
 

Citation

APA
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ICMJE
MLA
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Huber, A. M., Feldman, B. M., Rennebohm, R. M., Hicks, J. E., Lindsley, C. B., Perez, M. D., … Juvenile Dermatomyositis Disease Activity Collaborative Study Group, . (2004). Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies. Arthritis Rheum, 50(5), 1595–1603. https://doi.org/10.1002/art.20179
Huber, Adam M., Brian M. Feldman, Robert M. Rennebohm, Jeanne E. Hicks, Carol B. Lindsley, Maria D. Perez, Lawrence S. Zemel, et al. “Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies.Arthritis Rheum 50, no. 5 (May 2004): 1595–1603. https://doi.org/10.1002/art.20179.
Huber AM, Feldman BM, Rennebohm RM, Hicks JE, Lindsley CB, Perez MD, et al. Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies. Arthritis Rheum. 2004 May;50(5):1595–603.
Huber, Adam M., et al. “Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies.Arthritis Rheum, vol. 50, no. 5, May 2004, pp. 1595–603. Pubmed, doi:10.1002/art.20179.
Huber AM, Feldman BM, Rennebohm RM, Hicks JE, Lindsley CB, Perez MD, Zemel LS, Wallace CA, Ballinger SH, Passo MH, Reed AM, Summers RM, White PH, Katona IM, Miller FW, Lachenbruch PA, Rider LG, Juvenile Dermatomyositis Disease Activity Collaborative Study Group. Validation and clinical significance of the Childhood Myositis Assessment Scale for assessment of muscle function in the juvenile idiopathic inflammatory myopathies. Arthritis Rheum. 2004 May;50(5):1595–1603.
Journal cover image

Published In

Arthritis Rheum

DOI

ISSN

0004-3591

Publication Date

May 2004

Volume

50

Issue

5

Start / End Page

1595 / 1603

Location

United States

Related Subject Headings

  • Severity of Illness Index
  • Reproducibility of Results
  • Predictive Value of Tests
  • Outcome Assessment, Health Care
  • Observer Variation
  • Myositis
  • Motor Activity
  • Humans
  • Disability Evaluation
  • Child, Preschool