European Alliance of Associations for Rheumatology, EULAR Jun 5 2026 Idiopathic inflammatory myopathies (IIM) are a heterogenous group of autoimmune conditions with substantial morbidity. EULAR - The European Alliance of Associations for Rheumatology - in collaboration with the American College of Rheumatology (ACR) introduced classification criteria for the major subgroups in 2017, but there is a need for contemporary real-world data to understand the burden - and well as new ways of assessing