Document Type
Journal Article
Publication Date
2017
Journal
RMD Open: Rheumatic and Musculoskeletal Diseases
DOI
10.1136/rmdopen-2017-000507
Abstract
Objective To describe the methodology used to develop new classification criteria for adult and juvenile idiopathic inflammatory myopathies (IIMs) and their major subgroups.
Methods An international, multidisciplinary group of myositis experts produced a set of 93 potentially relevant variables to be tested for inclusion in the criteria. Rheumatology, dermatology, neurology and paediatric clinics worldwide collected data on 976 IIM cases (74% adults, 26% children) and 624 non-IIM comparator cases with mimicking conditions (82% adults, 18% children). The participating clinicians classified each case as IIM or non-IIM. Generally, the classification of any given patient was based on few variables, leaving remaining variables unmeasured. We investigated the strength of the association between all variables and between these and the disease status as determined by the physician. We considered three approaches: (1) a probability-score approach, (2) a sum-of-items approach criteria and (3) a classification-tree approach.
Results The approaches yielded several candidate models that were scrutinised with respect to statistical performance and clinical relevance. The probability-score approach showed superior statistical performance and clinical practicability and was therefore preferred over the others. We developed a classification tree for subclassification of patients with IIM. A calculator for electronic devices, such as computers and smartphones, facilitates the use of the European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria.
Conclusions The new EULAR/ACR classification criteria provide a patient’s probability of having IIM for use in clinical and research settings. The probability is based on a score obtained by summing the weights associated with a set of criteria items.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
APA Citation
Bottai, M., Tjärnlund, A., Santoni, G., Werth, V., Pilkington, C., The International Myositis Classification Criteria Project consortium, the Euromyositis register and the Juvenile Dermatomyositis Cohort Biomarker Study and Repository (JDRG) (UK and Ireland), & Mamyrova, G. (2017). EULAR/ACR classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups: a methodology report. RMD Open: Rheumatic and Musculoskeletal Diseases, (). http://dx.doi.org/10.1136/rmdopen-2017-000507
Peer Reviewed
1
Open Access
1
Comments
Reproduced with permission of BMJ Open. RMD Open: Rheumatic and Musculoskeletal Diseases