LAUSR

Juvenile idiopathic arthritis (JIA) is the most common type of arthritis in childhood (1). Prompt diagnosis is mandatory to avoid joint destruction and growth abnormalities. However, it’s often misdiagnosed by pediatricians and general practitioners leading to longer diagnosis delay (2).The aim of this study was to evaluate the lag time between JIA symptoms onset and diagnosis and its impact on disease activity and bone loss.A retrospective monocentric study was carried out on JIA patients (ILAR criteria). Diagnosis delay was collected from the patient’s medical files. Disease activity at JIA diagnosis was evaluated by JADAS10 (Juvenile Arthritis Disease Activity Score) in poly and oligoarticular subtypes and by BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) in arthritis related enthesitis form. The data were analyzed using the SPSS statistical package. A p value < 0.05 was considered significant.We enrolled 48 JIA (31 male and 17 female) with a mean age at disease onset of 11.2 ± 3.8 years. The median disease duration was 84 months [2-408]. The median JIA diagnosis delay was 8 months [1-108]. The JIA subgroups were in decreasing order of frequency: Enthesitis-related Arthritis (n=32), Polyarticular RF- (n=4), Polyarticular RF+ (n=2), Oligoarticular (n=6), Systemic (n=2), Psoriatic Arthritis (n=1) and Undifferentiated (n=1).At diagnosis, median ESR and CRP were 44 mm/hour [2-100] and 24 mg/l [2-86] respectively. Median JADAS10 score was 4 [0-21]. Median BASDAI score was 6.2 [2-9.4].At follow-up, five patients (10.4%) had atlantoaxial subluxation and 17 had coxitis (43.8%).At bone densitometry, 45% of patients had osteroposis and 27.5% had osteopenia.An agreement was assessed between a long diagnosis delay and the following parameters: male gender (p=0.04) and osteoporosis (p=0.018). A Significant positive correlation was found between delay in JIA diagnosis and BASDAI score (p=0.047, r=0.63). No association was found between JIA diagnosis delay and JADAS score (p=0.56). Neither ESR (p=0.19) nor CRP (p=0.42) was associated with JIA diagnosis delay.Finally, no link was observed with the occurrence of hip arthritis (p=0.281) or atlantoaxial subluxation (p=0.137).In this study, delay in diagnosis was associated with higher disease activity scores and bone loss. Our results suggest that early identification and treatment of JIA leads to improved outcomes as well as bone mass.[1]Petty R.E., Southwood T.R., Manners P. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. J Rheumatol. 2004;31(2):390.[2]Foster HE, Scott C, Tiderius CJ,et al. Improving musculoskeletal health for children and young people - A ‘call to action’. Best Pract Res Clin Rheumatol. 2020 Oct;34(5):101566.None declared