Testing the Model for Predicting Effectiveness of Anakinra in Systemic Juvenile Idiopathic Arthritis

Abstract

We read the article by Saccomanno, et al, "Predictors of effectiveness of anakinra in systemic juvenile idiopathic arthritis," with great interest 1. They reported that shorter disease duration, fewer active joints, higher ferritin levels, and greater activity of systemic manifestations were independently correlated with achievement of complete clinical response at 1 year (CCR1) in systemic juvenile idiopathic arthritis (sJIA). They proposed a model with 4 variables (disease duration ≤ 3.9 yrs, active joint count ≤ 10, ferritin > 444 ng/ml, systemic manifestation score > 3) to predict response to anakinra in sJIA 1. We have analyzed these variables and tested this model in our cohort of patients with sJIA. The patients (0-18 yrs old) treated with anakinra at Hacettepe University Pediatric Rheumatology Department between January 2006 and January 2018 were included. The patients were classified with sJIA according to the International League of Associations for Rheumatology criteria 2. Demographic data, clinical manifestations, laboratory findings, and CCR1 were documented. The study was approved by the ethics committee of Hacettepe University (GO 16/154) and written consent from the patients/parents was obtained according to the Declaration of Helsinki. These factors were the same as those stated in the article by Saccomanno, et al 1 : the definition for CCR (absence of fever, negative C-reactive protein, physician's global assessment ≤ 1, active joint count ≤ 1, and ≥ 75% reduction of corticosteroid dose from baseline), systemic manifestation score, and the inclusion/exclusion criteria for patients to keep the results comparable. The normality of distribution of numerical variables