THU0527 RISK SCORE OF MACROPHAGE ACTIVATION SYNDROME IN PATIENTS WITH SYSTEMIC JUVENILE IDIOPATHIC ARTHRITIS
Authors: Simone Carbogno, Denise Pires Marafon, Giulia Marucci, Manuela Pardeo, Antonella Insalaco, Virginia Messia, Emanuela Sacco, Ferhat Demir, Betül Sözeri, Alenka Gagro, Nastasia Kifer, Marija Jelusic, Francesca Minoia, Mikhail Kostik, Olga Vougiouka, Fabrizio De Benedetti, Claudia Bracaglia
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Macrophage Activation Syndrome (MAS) is a severe, life-threatening, complication of rheumatic diseases in childhood, particularly of systemic Juvenile Idiopathic Arthritis (sJIA), occurring in approximately 25% of the patients with sJIA. A score that identifies sJIA patients who are at high risk to develop MAS would be useful in clinical practice. <h3>Objectives:</h3> To evaluate whether routine laboratory parameters at disease onset may predict the development of MAS in patients with active sJIA. To define a risk score of MAS for sJIA patients using these parameters. <h3>Methods:</h3> Laboratory parameters of disease activity and severity (WBC, N, PLT, Hb, ferritin, AST, ALT, gGT, LDH, TGL, fibrinogen, D-dimer and CRP), were retrospectively evaluated in 86 sJIA patients referred to our Division of Rheumatology from 1998 to 2017 with at least one year of follow-up. Laboratory parameters were evaluated during active sJIA, without MAS, at time of hospitalization (T1) and before treatment for sJIA was started (T2). Patients were divided in two groups: group 1 (patients without history of MAS), group 2 (patients with at least one MAS episode during disease course). To calculate a MAS risk score, laboratory parameters, collected at T2, with a statistical significant difference between the two groups of patients were selected. <h3>Results:</h3> Thirty-three patients, who fulfilled the 2016 classification criteria for MAS [1] at time of sampling, were excluded from the analysis. Therefore, we analysed laboratory parameters of 53 patients with sJIA, 33 of whom without history of MAS (group 1) and 20 who developed at least one episode of MAS during disease course (group 2). Levels of ferritin, AST, LDH, gGT and TGL, collected at T2, were statistically significant higher in patients with a history of MAS compared to those without a history of MAS. For each of these parameters an arbitrary cut-off was defined. In order to define the final score an arbitrary rate was attributed to each parameter. Sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were calculated to define the best scoring system. The scoring system with the best sensitivity was chosen (Table 1). A MAS risk score &gt;3 identified 19 out of 20 sJIA patients with a history of MAS and 4 out of 33 sJIA patients without history of MAS. In order to validate the MAS risk score on a different population, we applied it on 53 patients from other paediatric Rheumatologic centres. Thirty-seven of these patients without history of MAS while 16 with at least one episode of MAS. Sensitivity and specificity were 0.750 and 0.784 respectively. <h3>Conclusion:</h3> In conclusion we developed a MAS risk score based on routine laboratory parameters that are available worldwide, that can help clinicians to identify patients at higher risk to develop MAS. A validation on a larger population is necessary. <h3>References:</h3> [1] Ravelli A et al. Ann Rheum Dis. 2016 Mar;75(3):481-9. <h3>Disclosure of Interests:</h3> Simone Carbogno: None declared, Denise Pires Marafon: None declared, Giulia Marucci: None declared, Manuela Pardeo: None declared, Antonella Insalaco: None declared, Virginia Messia: None declared, Emanuela Sacco: None declared, Ferhat Demir: None declared, Betül Sözeri: None declared, Alenka Gagro: None declared, Nastasia Kifer: None declared, Marija Jelusic: None declared, Francesca Minoia: None declared, Mikhail Kostik: None declared, Olga Vougiouka: None declared, Fabrizio De Benedetti Grant/research support from: Abbvie, SOBI, Novimmune, Roche, Novartis, Sanofi, Pfizer, Claudia Bracaglia: None declared