- Poster presentation
- Open Access
Progress report on development of classification criteria for adult and juvenile idiopathic inflammatory myopathies
- Clarissa Pilkington1, 2,
- Anna Tjärnlund3,
- Matteo Bottai4,
- Victoria Werth5,
- Marianne de Visser6,
- Lars Alfredsson7,
- Anthony Amato8,
- Richard J Barohn9,
- Matthew Liang10,
- Jasvinder Singh11,
- Frederick W Miller12,
- Lisa Rider12,
- Ingrid E Lundberg3 and
- the members of the International Myositis Classification Criteria Project
https://doi.org/10.1186/1546-0096-12-S1-P94
© Pilkington et al; licensee BioMed Central Ltd. 2014
- Published: 17 September 2014
Keywords
- Myopathy
- Muscle Biopsy
- Myositis
- Skin Rash
- Classification Criterion
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.
Performance of new and exisiting classification / diagnostic criteria for idiopathic inflammatory myopathies
Performance (%) | New classification criteriaa | Peter & Bohan [1]b | Tanimoto et al. [2] | Targoff et al. [3]b | Dalakas & Hohlfeld [4]b | Hoogendijk et al. [5]b | |
---|---|---|---|---|---|---|---|
Without muscle biopsy data | With muscle biopsy data | ||||||
Sensitivity | 91 | 94 | 98 | 96 | 93 | 6 | 51 |
Specificity | 82 | 85 | 55 | 31 | 88 | 99 | 96 |
Correctly classified | 88 | 91 | 86 | 79 | 91 | 45 | 70 |
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.
Authors’ Affiliations
Copyright
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.