# Transformation of juvenile idiopathic arthritis in adult-oriented rheumatology care

## TL;DR

This study examines how juvenile idiopathic arthritis changes when patients transition to adult rheumatology care, highlighting challenges in diagnosis and treatment.

## Contribution

The study identifies specific JIA subtypes that are difficult to classify using adult criteria during the transition to adult care.

## Key findings

- Enthesitis-related arthritis was the most common JIA subtype in pediatric patients.
- Many JIA patients were reclassified into adult rheumatology diagnoses like axial spondyloarthritis and rheumatoid arthritis.
- Oligoarticular and rheumatoid factor-negative polyarticular JIA subtypes were hardest to classify in adult-oriented care.

## Abstract

Juvenile idiopathic arthritis (JIA) is the most prevalent form of chronic inflammatory arthritis in children, and the symptoms persist into adulthood for a considerable number of patients. This study aimed to compare the JIA subtypes using the diagnostic criteria used for adults and identify the clinical characteristics and treatment approaches for patients with JIA transitioning to adult-oriented rheumatology care.

Patients diagnosed with JIA in the pediatric rheumatology clinic were retrospectively evaluated. The patients (n=107) who had at least one follow-up visit in the adult rheumatology clinic were included in the study. After transitioning from pediatric to adult-oriented rheumatology care, 2 experienced adult rheumatologists retrospectively reclassified the patients based on the adult classification criteria with clinical, serological, and radiological findings.

The most common diagnosis was enthesitis-related arthritis (49.5%), followed by oligoarticular JIA (22.4%). The follow-up diagnoses of the JIA patients in adult-oriented rheumatology care were radiographic axial spondyloarthritis (SpA) (30.8%), nonradiographic axial SpA (15%), rheumatoid arthritis (12.1%), Still’s disease (11.2%), psoriatic arthritis (2.8%), and peripheral SpA (2.8%). However, 25.2% of the patients were unclassified, particularly in the oligoarticular subgroup. During the transition, 60% of the patients with JIA were receiving medical treatment.

A significant number of patients in oligoarticular and rheumatoid factor-negative polyarticular JIA groups did not meet adult classification criteria, making them the most challenging subtypes to manage in adult-oriented rheumatology care. Understanding the transformation of distinct phenotypes into adulthood and managing the transition without interruption can improve the prognosis of JIA.