FRI0658 Prognostic markers for response according to the new acr/eular 2016 response criteria for idiopathic inflammatory myositis
Authors: F. Espinosa-Ortega, M. Holmqvist, M. Dastmalchi, I. Lundberg, H. Alexanderson
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background:</h3> Idiopathic inflammatory myopathies (IIM) is a heterogeneous group of chronic, inflammatory diseases with varying response to treatment. To date there is no biomarker to predict such response. Autoantibodies are found in up to 80% of patients with IIM; myositis associated (MAA) and myositis specific antibodies (MSA) are associated with certain clinical features. Whether MSAs can be used as biomarkers to predict response to treatment is unknown. <h3>Objectives:</h3> To investigate predictors of response according to the New ACR/EULAR 2016 response criteria for idiopathic inflammatory myositis using a national rheumatology register. <h3>Methods:</h3> Patients with IIM who were included in the Swedish Rheumatology Quality Register (SRQ) between January 1st, 2003 and December 31st, 2015 within 12 months of diagnosis were included in this study. Response was assessed at the visit registered closest to one year after inclusion. IIM subgroup (dermatomyositis (DM), polymyositis (PM) and overlap myositis), autoantibody profile, time to diagnosis and treatment were categorized into dichotomous variables. Time to diagnosis (from firts symptoms) less than 3 months was considered as early; initial dose of glucocorticoids was considered high when &gt;45 mg. The ACR/EULAR 2016 criteria for Clinical Response were applied to measure response, and it was categorized in minimal (20–39/100), moderate (40–59/100) and major (&gt;60/100) response. The association between response and clinical characteristics was assessed by multinomial logistic regression. <h3>Results:</h3> 179 patients were included. Median age at inclusion was 58.9 years (Interquartile range (IQR) 46.7–68.6), 65% were female and 49% had ever smoked. Thirty-three percent had DM, 45% PM and 22% overlap myositis. Lung disease was present in 37% and cancer within ±3 years from IIM diagnosis was present in 13%. Ninety-one percent were given glucocorticoid treatment, 72% immunosuppressive drugs, 22% cyclophosphamide and 13% a biological drug. <i>Response rates</i>. Two thirds (62%) were responders, 23% had minimal, 20% moderate and 18% major response. Minimal response was associated with high initial glucocorticoid dose (OR 3.4, CI95% 1.4–8.1); moderate response to high initial glucocorticoid dose (4.8 CI95% 1.9–11.8) and major response to early diagnosis (OR 3.9 CI95% 1.3–11.9), and high initial glucocorticoids dose (OR 9.5 CI95% 3.0–29.8). No associations between IIM subgroup, autoantibody profile and response rates were observed. <h3>Conclusions:</h3> Early and intensive treatment with high doses of glucocorticoids was associated with high rates of clinical response. These data suggest that early intensive immunosupressive treatment is important in IIM. <h3>References</h3> 1. Betteridge Z, McHugh N. Myositis-specific autoantibodies: an important tool to support diagnosis of myositis. J Intern Med2016;280:8–23. 2. Aggarwal R, et al. 2016American College of Rheumatology/European League Against Rheumatism criteria for minimal, moderate and major clinical response in adult dermatomyositis and polymyositis. Ann Rheum Dis2017;76:792–801. <h3>Acknowledgements:</h3> Börje Dahlin Foundation. <h3>Disclosure of Interest:</h3> None declared