Types of candidate definitions for response criteria that were developed and tested
| Type of candidate definitions of response | Description | Example of the candidate definition for the response criteria |
|---|---|---|
| Previously published (categorical definition) | Previously published response criteria that were retested | Minimal. Three of any 6 improved by ≥20%, no more than 1 worse by >30% (which cannot be CMAS)10 Moderate. Three of any 6 improved by ≥50%, no more than 1 worse by >30% (which cannot be CMAS)11 Major. Three of any 6 improved by ≥70%, no more than 1 worse by >30% (which cannot be CMAS)11 |
| Newly drafted (categorical definition) | Drafted relative or absolute per cent change in candidate definitions of response, based on recent CSM survey | Minimal. MD global, muscle strength (MMT or CMAS), and 1 other CSM improved by ≥20% Moderate. MD global, muscle strength (MMT or CMAS), and 1 other CSM improved by ≥30% Major. MD global, muscle strength (MMT or CMAS), and 1 other CSM improved by ≥50% |
| Weighted (categorical definition) | Applied conjoint analysis relative weights to CSM in newly drafted definitions; each CSM receives improvement points (corresponding relative weights) when it reaches the threshold for minimal, moderate, or major improvement; worsening points are applied similarly; improvement is calculated based on a total score of improvement vs worsening | Improvement=at least 3.5 improvement points of 10 total improvement points, and no more than 1.5 worsening points, where MD global=2 points, parent global=1 point, MMT/CMAS=3 points, C-HAQ=1.5 points, extramusc/DAS=1.5 points, enzyme/CHQ-PhS=1 point Minimal. Improvement points given when CSM ≥20%; worsening points given when CSM worse by >30% Moderate. Improvement points given when CSM ≥50%; worsening points given when CSM worse by >30% Major. Improvement points given when CSM ≥75%; worsening points given when CSM worse by >30% |
| Logistic regression (continuous definition) | Model of improvement using a combination of CSM with different weights, as developed in the logistic regression model; total scores derived, with different cutoffs for minimal, moderate, and major improvement Relative % change | Improvement score=(MD global % change)+0.5×(parent global activity % change)+0.5×(extramusc activity or DAS % change) Minimal. Improvement score ≥15 Moderate. Improvement score ≥30 Major. Improvement score ≥60 |
| CSM–weighted (continuous definition)* | Multiply the % change in each CSM by the weights derived from conjoint analysis, then sum (% change in each CSM×conjoint analysis weights) to get final total improvement score; different thresholds for minimal, moderate, and major improvement established based on consensus profile ratings as gold standard | Improvement score=2×(MD global % change)+(parent global % change)+3×(MMT or CMAS % change)+1.5×(C-HAQ % change)+1.5×(extramusc or DAS % change)+(enzyme or CHQ-PhS % change) Minimal. Improvement score ≥100 Moderate. Improvement score ≥250 Major. Improvement score ≥400 |
| Conjoint analysis (continuous definition) | For a given range in the level of improvement in each CSM, a score is assigned, as developed by the survey results and modelling; greater degrees of improvement receive higher scores; a patient is minimally improved if the improvement score is above the cutoff for minimal improvement; similarly for moderate and major improvement | Cut points for the model for juvenile DM are:
|
*This type of definition was not brought to the final consensus conference.
†The full absolute per cent change model is shown in table 3 and in online supplementary table S2 (available on the Arthritis & Rheumatology web site at http://onlinelibrary.wiley.com/doi/10.1002/art.40060/abstract).
C-HAQ, Childhood Health Assessment Questionnaire; CHQ-PhS, physical summary score of the Child Health Questionnaire–Parent Form 50; CMAS, Childhood Myositis Assessment Scale; CSM, core set measure; DAS, Disease Activity Score; DM, dermatomyositis; enzyme, most abnormal serum muscle enzyme value among aldolase, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and creatine kinase; extramusc, extramuscular global activity; MD global, physician global activity score; MMT, manual muscle testing; parent global, parent global activity score.