2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups

Abstract

Objective To develop and validate new classification criteria for adult and juvenile idiopathic inflammatory myopathies (IIM) and their major subgroups. Methods Candidate variables were assembled from published criteria and expert opinion using consensus methodology. Data were collected from 47 rheumatology, dermatology, neurology and pediatric clinics worldwide. Several statistical methods were utilized to derive the classification criteria. Results Based on data from 976 IIM patients (74% adults; 26% children) and 624 non-IIM patients with mimicking conditions (82% adults; 18% children) new criteria were derived. Each item is assigned a weighted score. The total score corresponds to a probability of having IIM. Sub-classification is performed using a classification tree. A probability cutoff of 55%, corresponding to a score of 5.5 (6.7 with muscle biopsy) “probable IIM”, had best sensitivity/specificity (87%/82% without biopsies, 93%/88% with biopsies) and is recommended as a minimum to classify a patient as having IIM. A probability of ≥90%, corresponding to a score of ≥7.5 (≥8.7 with muscle biopsy), corresponds to “definite IIM”. A probability of <50%, corresponding to a score of <5.3 (<6.5 with muscle biopsy) rules out IIM, leaving a probability of ≥50 to <55% as “possible IIM”. Conclusions The EULAR/ACR classification criteria for IIM have been endorsed by international rheumatology, dermatology, neurology and pediatric groups. They employ easily accessible and operationally defined elements, and have been partially validated. They allow classification of “definite”, “probable”, and “possible” IIM, in addition to the major subgroups of IIM, including juvenile IIM. They generally perform better than existing criteria.

Performance of the 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies in clinical practice

“…The criteria were tested for sensitivity, but not for specificity in two independent cohorts. 1 We evaluated the performance of these criteria in a retrospective cohort of consecutively diagnosed IIM cases administered at our secondary/tertiary rheumatology centre between January 2010 and October 2017. The controls were the consecutive patients, without proof of IIM, who had an extensive diagnostic work-up for IIM, including muscle biopsy, during the same time period.…”

Polymyositis, Dermatomyositis, and Statins: A Review

“…The classification of inflammatory myopathies has undergone several revisions [38][39][40] since the earliest descriptions by Bohan and Peter.…”

“…Besides clinical criteria, magnetic resonance imaging (MRI) [39,44] can be use-ful to make the right diagnosis. MRI with whole-body technique (WBMRI) is considered particularly useful for identifying the involvement of muscles: parameters such as inflammation, fibrosis, and atrophy can be used to determine the pattern of disease activity even at subclinical level [45][46][47][48][49].…”

“…Treatment with repository corticotropin injection (RCI) in a recent open label clinical trial [51] was effective, safe and tolerable, and led to a steroid dose reduction in adult patients with myositis refractory to glucocorticoid and traditional immunosuppressive drugs.…”

Interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) axis in idiopathic inflammatory myopathies and its association with laboratory and clinical parameters: a pilot study

“…Diagnosis were based on the Peter and Bohan criteria [7,8]. All the patients included in the study group met also the EULAR/ACR classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups-seven patients had define IIM, nine probable IIM [9]. Seventeen (17) age-and gender-matched healthy subjects were enrolled as the control group.…”