Sat0476 juvenile Idiopathic Arthritis in Singapore: A 10-Year Clinical Experience

Abstract

BackgroundJuvenile Idiopathic Arthritis (JIA) is the commonest inflammatory arthritis of childhood worldwide.ObjectivesTo describe the incidence, clinical characteristics and experience with JIA in Singapore over a 10-year period.MethodsA prospective study was conducted in KK Women’s & Children’s Hospital and National University Hospital, Singapore from Jan 2009-Dec 2018. JIA was defined and classified according to ILAR criteria1. Demographics and clinical information were collected for every patient diagnosed with JIA.Results379 children were diagnosed with JIA (60.2% male, 71.2% Chinese). Average estimated incidence was 5.8 per 100000/yr. Clinical characteristics and treatment used are summarized in Table 1.OverallSystemicOligo-articularPolyarticular (RF -)Polyarticular (RF +)PsoriaticERAUndifferen-tiatedN (%)379 (100)32 (8.4)133 (35.1)47 (12.4)13 (3.4)10 (2.6)137 (36.1)7 (1.8)Onset age, yr*10.4(6.6-13.3)6.6(4.5-10.1)8.5(5.1-12.1)7.9(3.5-12.8)9.9(7.1-13.5)13.3(6.2-14.3)12.2(10.0-14.3)9.7(6.2-13.5)Diagnosis age, yr*10.9(7.1-14.0)6.4(4.1-10.2)9.0(6.0-13.4)8.6(3.7-13.3)10.2(7.4-13.7)13.8(10.7-15.3)12.6(10.7-14.7)11.2(9.2-15.1)Lag time, mth*2.9(1.0 – 7.4)0.7(0.3-1.2)3.1(1.1-7.6)3.0(1.6-9.8)2.6(2.1-4.6)5.0(1.2-12.4)3.6(1.2-8.1)8.3(1.6-36.5) ANA (n = 253)Positive124 (32.9)11 (34.4)50 (40.3)23 (48.9)5 (38.5)8 (80.0)27 (20.0)0 (0.0) RF (n = 374)Positive23 (6.1)5 (17.2)2 (1.5)0 (0.0)13 (100.0)0 (0.0)2 (1.5)1 (14.3) HLA-B27 (n = 368)Positive112 (30.4)0 (0.0)4 (3.1)2 (4.3)0 (0.0)0 (0.0)104 (75.9)2 (28.6)Uveitis diagnosed11 (2.9)0 (0.0)6 (4.5)1 (2.1)0 (0.0)0 (0.0)4 (2.9)0 (0.0)DMARD use257 (67.8)21 (65.6)47 (35.3)40 (85.1)13 (100.0)10 (100.0)121 (88.3)5 (71.4)Biologic use145 (38.3)17 (53.1)17 (12.8)17 (36.2)9 (69.2)3 (30.0)79 (57.7)3 (42.9)Table 1. *Median (IQR). Rest expressed in n (%).Disease modifying anti-rheumatic drugs (DMARD) were used in 67.8%, and younger age of diagnosis (p=0.002), longer lag time (p=0.004), males (p=0.018) and ERA (p=0.043) predicted their use. 38.3% required biologics, and males (p=0.047), longer lag time (p=0.037) and HLA-B27 positivity (p=0.030) were associated with their use. Uveitis incidence was 2.9%; 54.5% had oligoarthritis, 36.4% ERA, 9.1% polyarthritis (RF-). Younger age at JIA diagnosis was associated with uveitis (p=0.030).ConclusionERA is the commonest subtype of JIA in our cohort, explaining the male predominance and higher HLA-B27 positivity as compared to the West2. Longer lag time was associated with DMARD and biologic use, likely due to more severe disease at presentation. HLA-B27 association with biologic use may predict ineffectiveness of DMARD. Uveitis incidence was low as compared to Western literature that cites a prevalence of 11-30%3,4. Young age at diagnosis is a risk factor for uveitis. Interestingly, ANA-positivity and female gender were not associated with uveitis cases.References[1] Petty RE, et al. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. J Rheumatol. 2004Feb;31(2):390-...