title: International consensus on a proposed score system for muscle biopsy evaluation in patients with juvenile dermatomyositis: a tool for potential use in clinical trials.
abstract: OBJECTIVE
  To devise and test a system with which to evaluate abnormalities on muscle biopsy samples obtained from children diagnosed with juvenile dermatomyositis (DM).
  
  
  METHODS
  We established an International Consensus Group on Juvenile DM Biopsy and carried out 2 phases of consensus process and scoring workshops. Biopsy sections (n = 33) were stained by standard methods. The scoring tool was based on 4 domains of change: inflammatory, vascular, muscle fiber, and connective tissue. Using a Latin square design, biopsy samples were scored by 11 experts for items in each domain, and for a global abnormality measure using a 10-cm visual analog score (VAS 0-10). The tool's reliability was assessed using an intraclass correlation coefficient (ICC) and scorer agreement (alpha) by determining variation in scorers' ratings.
  
  
  RESULTS
  There was good agreement in many items of the tool, and several items refined between the meetings improved in reliability and/or agreement. The inflammatory and muscle fiber domains had the highest reliability and agreement. The overall VAS score for abnormality had high agreement and reliability, reaching an ICC of 0.863 at the second consensus meeting.
  
  
  CONCLUSIONS
  We propose a provisional scoring system to measure abnormalities on muscle biopsy samples obtained from children with juvenile DM. This system needs to be validated, and then could be used in prospective studies to test which features of muscle pathology are prognostic of disease course or outcome. We suggest that the process we used could be a template for developing similar systems in other forms of myositis.
authors: University College London, London, UK. l.wedderburn@ich.ucl.ac.uk
authors: Lucy R
authors: LR
authors: Wedderburn
authors: Hemlata
authors: H
authors: Varsani
authors: Charles K C
authors: CK
authors: Li
authors: Katy R
authors: KR
authors: Newton
authors: Anthony A
authors: AA
authors: Amato
authors: Brenda
authors: B
authors: Banwell
authors: Kevin E
authors: KE
authors: Bove
authors: Andrea M
authors: AM
authors: Corse
authors: Alison
authors: A
authors: Emslie-Smith
authors: Brian
authors: B
authors: Harding
authors: Jessica
authors: J
authors: Hoogendijk
authors: Ingrid E
authors: IE
authors: Lundberg
authors: Suely
authors: S
authors: Marie
authors: Carlo
authors: C
authors: Minetti
authors: Inger
authors: I
authors: Nennesmo
authors: Elisabeth J
authors: EJ
authors: Rushing
authors: Caroline
authors: C
authors: Sewry
authors: Susan C
authors: SC
authors: Charman
authors: Clarissa A
authors: CA
authors: Pilkington
authors: Janice L
authors: JL
authors: Holton
mesh_terms: D000293:Adolescent; D001706:Biopsy; D002196:Capillaries; D002648:Child; D002986:Clinical Trials as Topic; D003882:Dermatomyositis / Q000145:classification* / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000473:pathology*