Objective: Juvenile Idiopathic Arthritis (JIA) is the most common inflammatory joint diseases in children. Early identification of prognostic factor was important to improvement of clinical outcome. Therefore the aim of this study was to assess the prognostic factors of clinical outcome in JIA patients in Saiful Anwar Hospital. 
Methods: A cohort study was conducted in JIA patients in Pediatric Allergy and Immunology Center in Saiful Anwar Hospital between 2017 and 2018. Patients were diagnosed by the International League of Associations for Rhematology (ILAR) criteria and several prognostic factors such as demographic, clinical and laboratory finding were evaluated. Clinical outcome was measured by JADAS-27 (Juvenile Arthritis Disease Activity) that consist of active joint count, physician and patient global assessment and the ESR, then compare the scoring that improve and does not improve.
Results: Thirteen JIA patients with a mean age of 11.23±3.11 were included in this study. There were patient with oligoarthritis (46.1%), polyarthritis (46,1%) and systemic form (7,8%). All patients were categorized have a high disease activity index at the beginning of investigation with the mean JADAS-27 score 11.47±3.58. There were 23.1% patients meeting remission criteria and 15.4% with moderate disease activity at the end of investigation. Poor clinical outcome that was defined as no improvement of JADAS-27 score correlated with polyarticular involvement (OR=12,0, p=0.045), leukocytosis (OR=5.0, p=0.012), thrombocytosis (OR=12.0, p=0.043), persistently high ESR (OR=28, p=0.015) and low level of Vitamin D (OR=2.95, p=0.012) from multivariate analysis. No correlations was found between sex, age of onset, nutritional status, health insurance, fever, anemia, CRP level, positive rheumatoid factor and clinical outcome. 
Conclusion: Prognostic factors related to poor clinical outcome in JIA were identified. To better define prognostic factors, further analysis with a large study participant and long term outcome should be made.