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

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