Skip to main content
  • Poster presentation
  • Open access
  • Published:

Nearly 20% of children are not correctly classified according to current ilar classification in a PRINTO dataset of more than 12,000 juvenile idiopathic arthritis patients


Juvenile idiopathic arthritis (JIA) is an exclusion diagnosis that encompasses all forms of arthritis that begin before the age of 16 years, persist for more than 6 weeks, and are of unknown origin. In the ILAR classification, this heterogeneous group of chronic arthritides has been categorized on clinical and laboratory grounds to try to identify homogeneous, mutually exclusive categories suitable for etiopathogenic studies. However, the ILAR classification is complex and includes several inclusion and exclusion criteria. As a result, the correct placement of a patient in a specific category is not simple.


To assess the rate of inappropriate classification in a large dataset of JIA patients collected by PRINTO members.


Patients enrolled in the multinational study of the EPidemiology, treatment and Outcome of Childhood Arthritis (EPOCA study) and in the Pharmacovigilance in patients treated with biologics± methotrexate study (Pharmachild) were merged in a single database, after exclusion of overlapping patients. The reasons that led to a “provisional” ILAR classification (i.e. lack of fitting into an ILAR category despite ILAR category attribution by the attending physician) in the two datasets and the queries regarding classification raised to the investigators by the PRINTO staff were analyzed and grouped into major categories according to the inclusion or exclusion criterion involved.


A total of 12,141 patients were included in the study. The Table shows, for each JIA subtype, the most frequent drawbacks leading to a provisional classification. Most problems were related to the lack of 2 determinations of rheumatoid factor (RF) at least 3 months apart, the missing data in the indication of the presence or absence of psoriasis in the patient or in the presence or absence of a history of psoriasis in a first degree relative, the lack of assessment of HLA-B27 antigen, or the discrepancies in data results in the indication of a family history of spondyloarthropathies.

Table 1


In current clinical practice nearly 20% of JIA patient were categorized according to physician diagnosis attribution despite the lack of fulfillment of the ILAR exclusion criteria. Most frequently, this was related to the lack of assessment of RF or the inconsistency in indication of the presence of psoriasis in a first-degree relative.

Disclosure of interest

None declared.

Author information

Authors and Affiliations



Rights and permissions

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Consolaro, A., Bovis, F., Alexeeva, E. et al. Nearly 20% of children are not correctly classified according to current ilar classification in a PRINTO dataset of more than 12,000 juvenile idiopathic arthritis patients. Pediatr Rheumatol 12 (Suppl 1), P176 (2014).

Download citation

  • Published:

  • DOI: