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About the Tools

In order to determine how myositis patients' illnesses change over time, information is collected from both physicians and patients in a standardized way.

Disease activity assesses the manifestations of myositis which are thought to be reversible that result directly from the inflammatory process, whereas disease damage are those persistent changes in anatomy, physiology, pathology or function which result from previously active disease and from complications of therapy or other events.

IMACS has developed a consensus on a set of Core Set Domains and Measures for the assessment of disease activity, disease damage and patient-reported outcomes in adult and juvenile myositis patients. They are as follows:

Disease Activity Core Set Measures

  • Physician Global Activity - Visual Analogue Scale/Likert
  • Patient/Parent Global Activity - Visual Analogue Scale/Likert
  • Muscle Strength - Manual Muscle Testing (MMT)
  • Physical Function - Health Assessment Questionnaire (HAQ), Childhood Health Assessment Questionnaire (CHAQ), Childhood Myositis Assessment Scale (CMAS)
  • Laboratory - Muscle enymes
  • Extra-Muscular Activity - Myositis Disease Activity Assessment Tool (MDAAT) [MyoAct, MITAX]

Disease Damage Core Set Measures

  • Myositis Damage Index
  • Physician Global Damage - Visual Analogue Scale/Likert
  • Patient/Parent Global Damage - Visual Analogue Scale/Likert
  • Muscle Strength - MMT
  • Physical Function - [C]HAQ

Patient Reported Outcomes

  • Health Related Quality of Life using SF-36/CHQ, PedsQL
  • Myositis-specific measure to be developed/validated
  • Patient-reported fatigue measures to be developed/validated

Reference for Consensus of Core Set Domains and Measures for the assessment of disease activity, disease damage and patient-reported outcomes in adult and juvenile myositis patients

Miller FW, Rider LG, Chung YL, Cooper R, Danko K, Farewell V, Lundberg I, Morrison C, Oakley L, Oakley I, Pilkington C, Vencovsky J, Vincent K, Scott DL, Isenberg DA. Proposed preliminary core set measures for disease outcome assessment in adult and juvenile idiopathic inflammatory myopathies. Rheumatology (Oxford), 2001 Nov 40(11):1262-73. [Pub Med]

Rider LG, Werth VP, Huber AM, Alexanderson H, Rao AP, Ruperto N, Herbelin L, Barohn R, Isenberg D, Miller FW. Measures of adult and juvenile dermatomyositis, polymyositis, and inclusion body myositis: Physician and Patient/Parent Global Activity, Manual Muscle Testing (MMT), Health Assessment Questionnaire (HAQ)/Childhood Health Assessment Questionnaire (C-HAQ), Childhood Myositis Assessment Scale (CMAS), Myositis Disease Activity Assessment Tool (MDAAT), Disease Activity Score (DAS), Short Form 36 (SF-36), Child Health Questionnaire (CHQ), physician global damage, Myositis Damage Index (MDI), Quantitative Muscle Testing (QMT), Myositis Functional Index-2 (FI-2), Myositis Activities Profile (MAP), Inclusion Body Myositis Functional Rating Scale (IBMFRS), Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), Cutaneous Assessment Tool (CAT), Dermatomyositis Skin Severity Index (DSSI), Skindex, and Dermatology Life Quality Index (DLQI). Arthritis Care Res (Hoboken). 2011 Nov;63 Suppl 11:S118-57. doi: 10.1002/acr.20532. Review. [Abstract] 

Tool Access

The IMACS tools are available via download at other portions of this website (see Disease Activity Core Set Measures, Disease Damage Core Set Measures, Patient Reported Outcomes). All users have access to all tool descriptions, the tools themselves, view any educational resources associated with the tools, as well as references (where applicable).

Content Types

The tools are available for download in the following media types:

Adobe PDF documents

Microsoft Word documents 

Flash presentations 

Myositis Response Criteria

IMACS, in collaboration with the Paediatric Rheumatology International Trials Organisation (PRINTO) has also developed and validated Criteria for Minimal, Moderate, and Major Clinical Response in Adult Dermatomyositis and Polymyositis and Juvenile Dermatomyositis, which combine these core set measures of disease activity and define clinically meaningful change in each of the core set activity measures. IMACS suggests that these 2016 ACR/EULAR approved criteria be used as outcome measures or endpoints for all therapeutic trials in adult and juvenile dermatomyositis and polymyositis.

For further information, see Myositis Response Criteria.