Application of the new PRINTO classification criteria for juvenile idiopathic arthritis in a sample of Portuguese patients

BACKGROUND

The International League of Associations for Rheumatology (ILAR) classification system for juvenile idiopathic arthritis (JIA) does not depict homogenous subgroups of disease. As to unify our language with the adult rheumatic diseases, the Pediatric Rheumatology International Trials Organization (PRINTO) is attempting to revise these criteria.

OBJECTIVE

To reclassify a JIA sample according to the new provisional PRINTO subsets: systemic JIA (sJIA), RF-positive JIA (RF-JIA), early-onset ANA-positive JIA (eoANA-JIA), enthesitis/spondylitis-related JIA (ESR-JIA), "other JIA" and "unclassified JIA".

METHODS

Retrospective study including JIA patients followed in a Pediatric Rheumatology Unit at a university hospital. Medical records were reviewed, and patients were reclassified as per the provisional PRINTO criteria.

RESULTS

Of a total of 104 patients, 41 (39.4%) were reclassified as "other JIA", 36 (34.6%) as eoANA-JIA, 15 (14.4%) as ESR-JIA, 8 (7.7%) as sJIA and 4 (3.8%) as RF-JIA. More than 90% of the oligoarticular JIA were reclassified into either eoANA-JIA or "other JIA". Only one negative RF polyarticular JIA converted to RF-JIA due to the presence of a positive anti-citrulinated peptide antibody (ACPA). The psoriatic arthritis (PsA) subgroup disappeared into eoANA-JIA (25%), ESR-JIA (25%) or "other JIA" (50%). There were significant differences in age of onset, but not on the gender ratio or uveitis presence. Antinuclear antibody was more frequent in females (p=0.035) and younger patients (p<0.001).

CONCLUSION

The number of affected joints and PsA features elapsed in favour of laboratory RF, ACPA and ANA traits. PsA and oligoarticular JIA were abolished. The "other JIA" entity is heterogenous and prevalent, claiming reformulation.

Clinical Features and Risk Factors of Uveitis in Korean Children with Juvenile Idiopathic Arthritis: A Retrospective Cohort Study

This study aimed to investigate the clinical features and risk factors of uveitis in Korean children with juvenile idiopathic arthritis (JIA). The medical records of JIA patients diagnosed between 2006 and 2019 and followed up for ≥1 year were retrospectively reviewed, and various factors including laboratory findings were analyzed for the risk of developing uveitis. JIA-associated uveitis (JIA-U) developed in 30 (9.8%) of 306 JIA patients. The mean age at the first uveitis development was 12.4 ± 5.7 years, which was 5.6 ± 3.7 years after the JIA diagnosis. The common JIA subtypes in the uveitis group were oligoarthritis-persistent (33.3%) and enthesitis-related arthritis (30.0%). The uveitis group had more baseline knee joint involvement (76.7% vs. 51.4%), which increased the risk of JIA-U during follow-up (p = 0.008). Patients with the oligoarthritis-persistent subtype developed JIA-U more frequently than those without it (20.0% vs. 7.8%; p = 0.016). The final visual acuity of JIA-U was tolerable (0.041 ± 0.103 logMAR). In Korean children with JIA, JIA-U may be associated with the oligoarthritis-persistent subtype and knee joint involvement.

A comparison of Juvenile Idiopathic Arthritis classification systems with the Research in Arthritis in Canadian Children, Emphasizing Outcomes (ReACCh-Out) cohort

OBJECTIVE

To compare International League of Associations for Rheumatology (ILAR) and Paediatric Rheumatology INternational Trials Organisation (PRINTO) classifications for juvenile idiopathic arthritis (JIA) using data from the Research in Arthritis in Canadian Children emphasizing Outcomes cohort (ReACCh-Out). The aim of the PRINTO classification, still in development, is to identify homogeneous groups of patients with JIA.

METHODS

We used data recorded within 7 months of diagnosis in 1228 patients to assign patients according to the two classification systems by computation. We compared the proportions of patient classified and the alignment of classified categories with clinical-biological subtypes and adult types of arthritis.

RESULTS

The PRINTO system classified 244 patients (19.9%) as Early-onset ANA-positive (EOANA), 157 (12.8%) as Enthesitis/Spondylitis-related, 38 (3.1%) as Systemic, and 10 (0.8%) as RF-positive JIA. Twelve percent of patients were unclassifiable using ILAR while 63.3% were unclassifiable using PRINTO criteria (777 Other JIA and 2 Unclassified JIA). In sensitivity analyses, >50% remained unclassifiable by PRINTO. ILAR categories aligned better with clinical-biological subtypes in 131 patients (χ² =44, p=0.005 versus χ² =15, p=0.07 for PRINTO), and with adult types of arthritis in 389 evaluable patients.

CONCLUSION

Current identified PRINTO disorders classify a minority of patients with JIA, leaving a large proportion with Other disorders requiring further characterization. Current PRINTO classifications do not appear to improve alignment with clinical-biological subtypes or adult forms of arthritis relative to the older ILAR system.