Performance of ENMC and EULAR/ACR classification systems applied to a single tertiary center cohort of dermatomyositis patients

Jan Zoske,Felix Kleefeld,Werner Stenzel,Corinna Preuße,Katrin Hahn,Elise Siegert,Udo Schneider

doi:10.1186/s42466-021-00159-4

Abstract

BackgroundThere have been numerous classification systems to diagnose corresponding myositis subtypes and select appropriate therapeutic measures. However, the lack of a broad consensus on diagnostic criteria has led to clinical uncertainties. The objective of this study was to compare two commonly used dermatomyositis-classification systems regarding their clinical practicability and to point out their specific advantages and disadvantages.MethodsThis study included 30 patients diagnosed with dermatomyositis at the Charité university hospital, Berlin, Germany from 2010 to 2017. Patient files with complete data and defined historical classifications were enrolled and ENMC (2003) and EULAR/ACR (2017) criteria retrospectively applied.ResultsAccording to the ENMC approach, 14 patients were classified as "definite" and 12 as "probable" dermatomyositis. One patient exhibited an "amyopathic dermatomyositis" and three a "DM without dermatitis". Regarding the criteria probability of the EULAR/ACR set, 16 patients had a "high", 13 a "medium" and one a "low probability". There was a significant difference (p = 0.004) between the subclasses of the ENMC in relation to the EULAR/ACR score. The agreement between the classification probabilities of "definite/high" (κ = 0.400) and "possible/medium" (κ = 0.324) was fair.ConclusionsIt is important to find a consensus among the medical disciplines involved and to establish a structured procedure. Future studies with newer approaches are warranted to conclusively decide which system to use for the physician.

Highlights

Idiopathic inflammatory myopathies (IIM) are rare heterogeneous diseases characterized by inflammation in the skeletal muscles and resulting muscle weakness [1]
In 2017, new dermatomyositis classification criteria according to the European League against Rheumatism (EULAR) and the American College of Rheumatology (ACR) were proposed which were validated through 976 patients with idiopathic inflammatory myopathies as well as 624 non-myopathic controls [10, 11]
Applicability of the European Neuromuscular Centre (ENMC) and EULAR/ACR criteria was mandatory for our analysis

Summary

Introduction

Idiopathic inflammatory myopathies (IIM) are rare heterogeneous diseases characterized by inflammation in the skeletal muscles and resulting muscle weakness [1]. (2021) 3:59 workshop (2003 ENMC–IIM) revised dermatomyositis, polymyositis and inclusion body myositis (IBM) classification and proposed two additional categories These are called immune-mediated necrotising myopathy (IMNM) and non-specific myositis. The lack of a broad clinical consensus has resulted in diagnostic uncertainties in clinical practice for many physicians, especially those who do not deal with the latest findings on a daily basis and need clear guidelines [12, 14]. This individual change in diagnostics is evident in the systems used and compared in this study. The objective of this study was to compare two commonly used dermatomyositis-classification systems regarding their clinical practicability and to point out their specific advantages and disadvantages

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Conclusion