Registry of idiopathic inflammatory myopathies (REMAS) from nine Brazilian research centers linked to tertiary care and teaching hospitals

Idiopathic inflammatory myopathies (IIMs) are a group of rare chronic inflammatory diseases that affect the muscle, skin, and other organs. There is a severe lack of evidence for current treatment protocols for IIMs. The rarity of these conditions requires multicenter collaboration is vital to facilitate studies of pathogenesis, demographic, clinical, laboratory manifestations, comorbidities, treatment, and disease outcomes from that research group we established a national registry (REMAS) that aims to improve knowledge, facilitate research and clinical trials, and ultimately improve outcomes for these patients. A Brazilian network of nine centers and a research group was established to include, since December 2022, consecutive patients with dermatomyositis (DM), clinically amyopathic DM (CADM), inclusion body myositis (IBM), polymyositis (PM), immune-mediated necrotizing myopathy (IMNM), and anti-synthetase syndrome (ASyS). Currently, the study has recruited 284 patients, the majority were diagnosed with DM (53.1%), were female (77.1%), and Caucasian (44%). The median age was 51 years (IQR: 41–62), the median age at the disease onset was 43 years (IQR: 33–55), and the median duration of disease was 6 years (2–11). The median of the manual muscle test 8 (MMT-8) was 77 (74–80), the patient visual analogue scale (VAS) was 3 (0–5), physician VAS was 2 (0–5) and the Health Assessment Questionnaire of 0.33 (0.00–1.00), whereas median creatine kinase levels at the inclusion were 145 U/L (74–327). Among those positive for myositis-specific autoantibody, anti-Jo-1 was the most frequent (10.5%), followed by anti-Ro-52 (10.1%). Regarding treatment, 87% of the patients received prednisone with a median dose of 5 mg/day (0–20), 32.7% received pulse therapy with methylprednisolone, and 18.3% received human intravenous immunoglobulin. This establishment of this multicenter registry has facilitated research and advanced knowledge on a complex group of rare musculoskeletal diseases. The establishment of the REMAS has highlighted important local findings, despite limited representation from some regions of Brazil.