A67: Factors That Contribute to Classification of Children as Having Undifferentiated Juvenile Idiopathic Arthritis. Issue 11 (March 2014)

• Record Type: Journal Article
• Authors: Chan, Mercedes O.; Petty, Ross E.; Oen, Kiem; Duffy, Ciarán M.; Tucker, Lori B.; Yeung, Rae SM; Guzman, Jaime
• Is Part Of: Arthritis & rheumatology. Volume 66:Issue 11(2014)supplement
• Page Start: S98
• Page End: S98
• Publication Date: 2014-03
• Subjects: Arthritis -- Periodicals; Rheumatism -- Periodicals; 616.72
• DOI: 10.1002/art.38483
• Languages: English
• ISSNs: 2326-5191

Abstract

Abstract : Background/Purpose: According to the ILAR criteria, undifferentiated juvenile idiopathic arthritis (U‐JIA) includes children who fail to meet criteria for 1 of the other 6 categories or who meet criteria in more than 1 category. Classification requires category‐specific application of 5 exclusion criteria: 1. Psoriasis in the patient or a 1 st degree relative; 2. Arthritis beginning after the 6 th birthday in an HLA‐B27 + male; 3. HLAB27 associated disease in a 1st degree relative; 4. Rheumatoid factor positivity (RF+) on 2 occasions; and 5. The presence of systemic JIA (SoJIA). A pilot single‐centre study (n=21) revealed that psoriasis in a 1st degree relative was the most common reason for classifying patients as U‐JIA; disregarding this criterion would allow re‐classification of most U‐JIA patients and had no impact on the classification of JPsA patients (Chan et al., 2011). We aimed to determine the most frequent reasons for classifying children as U‐JIA from a large multicenter prospective cohort of children with JIA (n=1104). Methods: Two investigators reviewed data on patients diagnosed with UJIA extracted from the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh‐Out) database. They identified by consensus the reasons for classifying patients as U‐JIA and the JIA category they would fall in if the following two changes were made: disregarding psoriasis in a 1 st degree relative, considering patients as RF negative when only a single positive RF test was recorded. Results: 84 patients (51 female), were classified as U‐JIA for the reasons shown in the 1 . If the criterion of having a 1 st degree relative with psoriasis was disregarded, 25 patients would be classified as oligo JIA, 13 poly RF−, 5 poly RF+, 12 ERA and 2 SoJIA. If a single positive RF test was considered to be insufficient to meet the ILAR criterion of RF positivity, 9 patients would be re‐classified as oligo JIA, 5 ERA, 1 SoJIA, 1 JPsA and 1 would remain U‐JIA. Conclusion: Psoriasis in a 1 st degree relative is the most common factor contributing to the classification of a child as having U‐JIA and removing it from the existing criteria should be considered. The presence of a single positive test for RF was the second most common reason resulting in a classification of U‐JIA. Definitive RF testing (two tests) should be maintained to satisfy the criterion of "RF positivity".