- Poster presentation
- Open Access
- Published:
Progress report on development of classification criteria for adult and juvenile idiopathic inflammatory myopathies
Pediatric Rheumatology volume 12, Article number: P94 (2014)
Introduction
Classification criteria are needed to aid recruitment of appropriate patients into research studies. The International Myositis Classification Criteria Project (IMCCP) was set up with support from ACR and EULAR.
Objectives
To develop and validate new classification criteria for adult and juvenile IIM.
Methods
Candidate criteria variables were taken from published criteria and inclusion criteria from clinical trials of myositis. Comparator groups confused with IIM were defined. Clinical and laboratory data from IIM and comparator patients were collected from 47 rheumatology, dermatology, neurology and pediatrics clinics worldwide from 2008-2011.
Pair-wise associations among all items and between each item and clinicians’ diagnoses were assessed. Three approaches for derivation of classification criteria were explored: Traditional, Probability score and Classification tree.
Internal validation using bootstrap methods and external validation using data from the Euromyositis register and the Juvenile Dermatomyositis cohort biomarker study and repository UK and Ireland was performed.
Results
976 IIM (74% adults; 26% children) and 624 comparators (81% adults; 19% children) were obtained.
The new criteria comprise clinical items on muscles, skin, and laboratory measures. Muscle biopsy features can be included. Each item has an assigned score, the total score corresponds to the probability of having IIM. Each probability has specific sensitivity/specificity measures making it possible to use individual inclusion criteria for clinical studies. If no skin rash is present a muscle biopsy is mandatory. High probability of IIM is considered if the score > 7.5 (or > 8.7 if no skin rash), with minimum probability cutoff of 50% (score 5.3 or 6.5). Table 1.
External validation using data on 592 adult or 332 juvenile IIM patients yielded 100% sensitivity.
Conclusion
The new classification criteria for IIM have easy-to-access items and show generally superior performance compared to existing criteria. Approval for these will be sought from ACR/EULAR.
Disclosure of interest
None declared.
Author information
Affiliations
Consortia
Corresponding author
Rights and permissions
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
About this article
Cite this article
Pilkington, C., Tjärnlund, A., Bottai, M. et al. Progress report on development of classification criteria for adult and juvenile idiopathic inflammatory myopathies. Pediatr Rheumatol 12, P94 (2014). https://doi.org/10.1186/1546-0096-12-S1-P94
Published:
Keywords
- Myopathy
- Muscle Biopsy
- Myositis
- Skin Rash
- Classification Criterion
