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Myositis Response Criteria

IMACS and PRINTO, the Pediatric International Trials Organisation, have partnered with an international group of myositis experts to develop standardized clinical response criteria to assess minimal, moderate and major clinical improvement in patients with adult dermatomyositis and juvenile dermatomyositis.  These criteria, which have now been accepted by the American College of Rheumatology and European League Against Rheumatism, are recommended for use as primary endpoints in myositis therapeutic trials.  The criteria use the 6 IMACS or 6 PRINTO core set measures, combining the absolute percentage change in each with varying weights to obtain a Total Improvement Score on a scale of 0-100. Different thresholds of improvement have been set for minimal, moderate and major response, and these response thresholds also differ between adult and pediatric patients. The criteria may be used as a continuous outcome measure, using the Total Improvement Score, or as a categorical outcome of improvement (minimal, moderate or major improvement) and thus are a hybrid measure.

Final 2016 ACR/EULAR Criteria for Minimal, Moderate, and Major Clinical Response in Adult Dermatomyositis and Polymyositis and Juvenile Dermatomyositis

 

Web Calculators to Calculate the New Response Criteria

Two separate online calculators for the 2016 ACR/EULAR Myositis Response Criteria are available - one for adult dermatomyositis/polymyositis and one for juvenile dermatomyositis, allowing for easy, practical use of the response criteria.  These calculators require inputting of baseline and follow-up values for all 6 core set activity measures.  The maximum potential manual muscle testing score and the upper limit of the serum muscle enzymes must also be inputted; enzymes are expressed in Unit/L or microkat/L. For the pediatric calculator, the IMACS or PRINTO measures may be used. At minimum, the calculator requires input of the Physician Global Activity, Manual Muscle Testing (or Childhood Myositis Assessment Scale) and at least 2 other core set measures to provide a calculation of response. The Total Improvement Score will also be obtained.

To download the calculators for offline use, please right click the calculator link and select the option to "Save Link (or Target) As..."

Publications of the Response Criteria

Endorsement of these Criteria by the American College of Rheumatology and European League Against Rheumatism

Background on the New Response Criteria

Programs for the New Response Criteria

Two separate programs for the 2016 ACR/EULAR Myositis Response Criteria are available - one for adult dermatomyositis/polymyositis and one for juvenile dermatomyositis, allowing for easy, practical use of the response criteria. These programs are designed to be used on clinical trial or study data, versus the online calculator that was designed for single patient use. In addition to producing the 2016 ACR/EULAR Myositis Response Criteria, these programs calculate the response for the other top four candidate response criteria from the publications as well. These programs require inputting of core set measures into a Data Collection Tool (provided CSV file). The programs are designed to run in a PC SAS environment, but the programming language can easily be converted to other statistical programs. The following programs and user guides are available upon request.

  • Program for the 2016 ACR/EULAR Criteria for Minimal, Moderate, and Major Clinical Response in Adult Dermatomyositis and Polymyositis and other top four candidate criteria 
    Contents:
    • User Guide
    • Program Code for the response criteria
    • Data Collection Tool
    • Data Dictionary
  • Users Guide for the Adult Dermatomyositis and Polymyositis Response Criteria Program 
    Exercise: To help ensure your programs are running accurately, a test data set and corresponding output file is provided below. This will allow you to read in this dataset, then compare your output with the one provided.
    • Adult cross-validation test data set 
    • Adult cross-validation output file 

  • Program for the 2016 ACR/EULAR Criteria for Minimal, Moderate, and Major Clinical Response in Juvenile Dermatomysotis and other top four candidate criteria 
    Contents:
    • User Guide
    • Program Code for the response criteria
    • Data Collection Tool
    • Data Dictionary
  • Users Guide for the Juvenile Dermatomyositis Response Criteria Program 
    Exercise: To help ensure your programs are running accurately, a test data set and corresponding output file is provided below. This will allow you to read in this dataset, then compare your output with the one provided.
    • Pediatric cross-validation test data set 
    • Pediatric cross-validation output file 

Web-based Data Repository

Available soon

Definitions of Improvement

IMACS and PRINTO have previously developed and partially validated Preliminary Definitions of Improvement for Adult and Juvenile Myositis and Provisional Criteria for Response to Therapy, respectively, which combine core set measures of disease activity and define a minimal degree of clinically meaningful change in each of the core set activity measures. These criteria were published and previously used as endpoints in myositis therapeutic trials. The PRINTO provisional response criteria, with the addition of new thresholds for moderate and major improvement, has been accepted among the top 5 candidate criteria for juvenile dermatomyositis to include as a secondary endpoint in clinical trials.  These criteria/definitions of improvement are otherwise no longer recommended for use.

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