Real-life data on treatment strategies for polyarticular juvenile idiopathic arthritis

Polyarticular juvenile idiopathic arthritis (pJIA) is one of the most difficult subgroups of JIA to manage. The aim of this study is to compare patients who were started on MTX at diagnosis and continued on monotherapy during follow-up with patients who later required the addition of bDMARDs. Patients with pJIA following up between January 2013 and December 2023 were included in the study. The juvenile arthritis disease activity score (JADAS) was used for disease activity, and the juvenile arthritis damage index (JADI) was used for damage status. The study included 78 pJIA patients, 56 (71.8%) of whom were girls. The median age at the time of pJIA diagnosis was 11.3 (IQR 6.6-14.3) years. The patients were divided into two groups: those receiving only methotrexate (MTX) (n = 23, 29.5%) and those receiving MTX and biologic disease-modifying anti-rheumatic drugs (bDMARDs) (n = 55, 70.5%). The time elapsed until diagnosis, elbow involvement, duration of follow-up, and time to achieve clinically inactive disease were all significantly higher in patients receiving MTX + bDMARDs (p < 0.05). No significant difference was observed in the JADAS-71 value at diagnosis (p > 0.05). The JADAS-71 and JADI values at the 3rd, 6th, and 12th months were also significantly higher in patients receiving MTX and bDMARDs (p < 0.05).

Patients with pJIA can achieve remission with conventional DMARDs alone, such as methotrexate. Patients with high JADAS-71 and JADI-Articular (JADI-A) values may require the use of bDMARDs. In particular, high JADAS-71 values detected at the 6th month can be used as a predictor for starting bDMARDs in pJIA patients.

• Polyarticular JIA is a challenging subtype with heterogeneous treatment responses. • Objective tools such as JADAS-71 are widely used to assess disease activity and support treatment monitoring.

• JADAS-71 serves as a valuable tool to guide the timing of biologic therapy initiation in pJIA patients. • Although the management of pJIA is challenging for clinicians, some patients may achieve remission with only MTX.